@article{PeikowMaternPeteretal.2005, author = {Peikow, Dirk and Matern, Christa-Maria and Peter, Martin G. and Schilde, Uwe}, title = {Crystal structure of (1,4,7,10,13-pentaoxacyclopentadecane-O,O ',O '',O ''')(trifluoromethanesulfonato-O,O ')sodium, Na(C10H20O5)(CF3SO3)}, year = {2005}, abstract = {C11H20F3NaO8S, monoclinic, P121/nil (no. 11), a = 7.947(1) angstrom, b = 12.056(1) angstrom, c = 9.083(1) angstrom, P = 106.01 (1)degrees, V = 836.4 angstrom(3), Z = 2, R-gt(F) = 0.043, wR(ref)(F-2) = 0.120, T = 210 K.}, language = {en} } @article{AlarconAldereteAguilaetal.2005, author = {Alarcon, Julio and Alderete, Joel B. and Aguila, Sergio and Peter, Martin G.}, title = {Regio and stereoselective hydroxylation of alpha-agarofuran by biotransformation of rhizopus nigricans}, year = {2005}, abstract = {A new synthesis of 9 alpha-hydroxy-alpha-agarofuran (6 alpha) is described, using a microbiological hydroxylation alpha-agarofuran (5) as the key reaction. The stereochemistry of the biohydroxylation was determined on the basis of a NOESY-experiment and GIAO calculations at the B3LYP/cc-pVDZ level. A strong gamma-effect was observed at C15 of the agarofuran ring which was correctly predicted by the GIAO-B3LYP calculations}, language = {en} } @article{FotieNkengfackPeteretal.2004, author = {Fotie, J. and Nkengfack, A. E. and Peter, Martin G. and Heydenreich, Matthias and Fomum, Z. T.}, title = {Chemical constituents of the ethyl acetate extracts of the stem bark and fruits of Dichrostachys cinerea and the roots of Parkia bicolor}, issn = {1011-3924}, year = {2004}, abstract = {The antibacterial activities of ethyl acetate, methanol and aqueous extracts of the stem bark of Dichrostachys cinerea and the roots of Parkia bicolor have been evaluated. Ethyl acetate extracts have been investigated, studies that led to a series of known compounds, amongst which many are reported here for the very first time from both the species}, language = {en} } @article{BerthDautzenbergPeter1998, author = {Berth, Gisela and Dautzenberg, Herbert and Peter, Martin G.}, title = {Physica-chemical characterization of chitosans in dilute solution}, isbn = {2-907922-57-2}, year = {1998}, language = {en} } @article{VaajeKolstadVasellaPeteretal.2004, author = {Vaaje-Kolstad, G. and Vasella, A. and Peter, Martin G. and Netter, C. and Houston, Douglas R. and Westereng, B. and Synstad, Bjoenar and Eijsink, Vincent G. H. and van Aalten, Daan M. F.}, title = {Interactions of a family 18 chitinase with the designed inhibitor HM508 and its degradation product, chitobiono- delta-lactone}, issn = {0021-9258}, year = {2004}, abstract = {We describe enzymological and structural analyses of the interaction between the family 18 chitinase ChiB from Serratia marcescens and the designed inhibitor N,N'-diacetylchitobionoxime-N-phenylcarbamate (HM508). HM508 acts as a competitive inhibitor of this enzyme with a K-i in the 50 muM range. Active site mutants of ChiB show K-i values ranging from 1 to 200 muM, providing insight into some of the interactions that determine inhibitor affinity. Interestingly, the wild type enzyme slowly degrades HM508, but the inhibitor is essentially stable in the presence of the moderately active D142N mutant of ChiB. The crystal structure of the D142N-HM508 complex revealed that the two sugar moieties bind to the -2 and -1 subsites, whereas the phenyl group interacts with aromatic side chains that line the +1 and +2 subsites. Enzymatic degradation of HM508, as well as a Trp-->Ala mutation in the +2 subsite of ChiB, led to reduced affinity for the inhibitor, showing that interactions between the phenyl group and the enzyme contribute to binding. Interestingly, a complex of enzymatically degraded HM508 with the wild type enzyme showed a chitobiono-delta- lactone bound in the -2 and -1 subsites, despite the fact that the equilibrium between the lactone and the hydroxy acid forms in solution lies far toward the latter. This shows that the active site preferentially binds the E-4 conformation of the -1 sugar, which resembles the proposed transition state of the reaction}, language = {en} } @article{VaajeKolstadHoustonRaoetal.2004, author = {Vaaje-Kolstad, G. and Houston, Douglas R. and Rao, F. V. and Peter, Martin G. and Synstad, Bjoenar and van Aalten, Daan M. F. and Eijsink, Vincent G. H.}, title = {Structure of the D142N mutant of the family 18 chitinase ChiB from Serratia marcescens and its complex with allosamidin}, issn = {1570-9639}, year = {2004}, abstract = {Catalysis by ChiB, a family 18 chitinase from Serratia marcescens, involves a conformational change of Asp142 which is part of a characteristic D140XD142XE144 sequence motif In the free enzyme Asp142 points towards Asp140, whereas it rotates towards the catalytic acid, Glu144, upon ligand binding. Mutation of Asp142 to Asn reduced k(cat) and affinity for allosamidin, a competitive inhibitor. The X-ray structure of the D142N mutant showed that Asn142 points towards Glu144 in the absence of a ligand. The active site also showed other structural adjustments (Tyr10, Ser93) that had previously been observed in the wild-type enzyme upon substrate binding. The X-ray structure of a complex of D142N with allosamidin, a pseudotrisaccharide competitive inhibitor, was essentially identical to that of the wild-type enzyme in complex with the same compound. Thus, the reduced allosamidin affinity in the mutant is not caused by structural changes but solely by the loss of electrostatic interactions with Asp142. The importance of electrostatics was further confirmed by the pH dependence of catalysis and allosamidin inhibition. The pH-dependent apparent affinities for allosamidin were not correlated with k(cat), indicating that it is probably better to view the inhibitor as a mimic of the oxazolinium ion reaction intermediate than as a transition state analogue. (C) 2003 Elsevier B.V. All rights reserved}, language = {en} } @article{GermerMuggePeteretal.2003, author = {Germer, Antje and Mugge, Clemens and Peter, Martin G. and Rottmann, Antje and Kleinpeter, Erich}, title = {Solution- and bound-state conformational study of N,N',N''-triacetyl chitotriose and other analogous potential inhibitors of hevamine: Application of trNOESY and STD NMR spectroscopy}, year = {2003}, abstract = {The soln.-state conformations of N,N',N''-triacetyl chitotriose (1) and other potential chitinase inhibitors 2-4 were studied using a combination of NMR spectroscopy (NOESY) and mol. mechanics calcns. Detn. solely of the global energy min. conformation was found to be insufficient for an agreement with the NMR results. An appropriate consistency between the NMR exptl. data and theor. calcns. was only reached by assessing the structures as population-weighted av. conformers based on Boltzmann distributions derived from the calcd. relative energies. Analogies, but also particular differences, between the synthetic compds. 2-4 and the naturally-occurring N,N',N''-triacetyl chitotriose were found. Furthermore, the conformation of compds. 1 and 2 when bound to hevamine was also studied using transferred NOESY expts. and the binding process was found to impart a level of conformational restriction on the ligands. The preferred conformation as detd. for 1 in the bound state to hevamine belonged to one of the conformational families found for the compd. when free in soln., although full characterization of the bound-state conformations was impeded due to severe signal overlap. Satn. transfer difference NMR expts. were also employed to analyze the binding epitopes of the bound compds. We thus detd. that it is mainly the acetyl amido groups of the trisaccharide and the heterocyclic moiety which are in close contact with hevamine.}, language = {en} } @article{EijsinkSynstadGaseidnesetal.2003, author = {Eijsink, Vincent G. H. and Synstad, Bjoenar and Gaseidnes, Sigrid and Komander, David and Houston, Douglas R. and Peter, Martin G. and van Aalten, Daan M. F.}, title = {Structure and function of chitinolytic enzymes}, isbn = {82-471-5901-5}, year = {2003}, abstract = {The recent work on a variety of family 18 chitonolytic enzymes has yielded important data concerning the structure, substrate-binding, catalysis, inhibitor-binding and even dynamics. These data have been useful in helping to better understand the roles of various types of chitinases in chitin hydrolysis, to rationally engineer the properties of these enzymes, thus making them more suitable as biocatalysts, and to study and understand the effectiveness of natural and designed chitinase inhibitors, which may be of medical interest. On the other hand, the recent work on ChiB shows that catalysis in family 18 chitinases is a highly complicated process, involving larger parts of the enzyme and dynamics. Thus, despite recent discoveries, there is still a lot more to discover about how these enzyme work.}, language = {en} } @phdthesis{BahrkeEinarssonGislasonetal.2003, author = {Bahrke, Sven and Einarsson, Jon M. and Gislason, Johannes and Haebel, Sophie and Peter-Katalinic, Jasna and Peter, Martin G.}, title = {Characterization of chitooligosaccharides by mass spectrometry}, isbn = {82-47-15901-5}, year = {2003}, language = {en} } @article{KamlageSefkowZimmermannetal.2002, author = {Kamlage, Stefan and Sefkow, Michael and Zimmermann, Nicole and Peter, Martin G.}, title = {Concise synthesis of (+)-beta-benzyl gamma-butyrolactones from butynediol}, year = {2002}, language = {en} } @article{Peter2002, author = {Peter, Martin G.}, title = {Chitin and Chitosan from Animal Sources}, isbn = {3-527-30227-1}, year = {2002}, abstract = {A review on the chem. and biochem. of chitin and the chem. and application of chitosan. The following topics were discussed: structure of chitin and chitosan; occurrence and physiol. functions of chitin; detection of chitin in animals and anal. of chitin and chitosan; biosynthesis and biodegrdn. of chitin in animals; prodn. of chitin and chitosan; properties of chitin and chitosan; and applications of chitin and chitosan.}, language = {en} } @article{Peter2002, author = {Peter, Martin G.}, title = {Chitin and Chitosan from Fungi}, isbn = {3-527-30227-1}, year = {2002}, language = {en} } @misc{FerenzPeterBerg1983, author = {Ferenz, Hans-J{\"u}rgen and Peter, Martin G. and Berg, Dieter}, title = {Inhibition of farnesoic acid methyltransferase by sinefungin}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17016}, year = {1983}, abstract = {Sinefungin inhibited the S-adenosylmethionine-dependent farnesoic acid methyltransferase in a cell-free system containing a homogenate of corpora allata from female locusts, Locusta migratoria. The enzyme catalyzed the penultimate step of juvenile hormone biosynthesis in the insects. Culturing corpora allata in the presence of sinefungin greatly suppressed juvenile hormone production. The following in vivo effects were visible after injection of the inhibitor: increase in mortality and reduction of total haemolymph protein liter and ovary fresh weight, as well as length of terminal oocytes. Attempts to reverse these effects by topical application of the juvenile hormone analog ZR-515 (methoprene) were only partly successful. Therefore, the in vivo effects may be due to a general inhibition of methyltransferase enzymes in the insect. Sinefungin appeared to be of potential interest as the first representative of a new class of insect growth regulators.}, language = {en} } @misc{KortPeterKoopmanschap1983, author = {Kort, C. A. D. de and Peter, Martin G. and Koopmanschap, A. B.}, title = {Binding and degradation of juvenile hormone III by haemolymph proteins of the Colorado potato beetle: a re-examination}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16777}, year = {1983}, abstract = {The haemolymph of the adult Colorado potato beetle, Lepinotarsa decemlineata Say, contains a high molecular weight (MW > 200,000) JH-III specific binding protein. The Kd value of the protein for racemic JH-III is 1.3 ± 0.2 × 10-7 M. It has a lower affinity for racemic JH-I and it does not bind JH-III-diol or JH-III-acid. The binding protein does discriminate between the enantiomers of synthetic, racemic JH-III as was determined by stereochemical anaysis of the bound and the free JH-III. Incubation of racemic JH-III with crude haemolymph results in preferential formation of (10S)-JH-III-acid, the unnatural configuration. The JH-esterase present in L. decemlineata haemolymph is not enantioselective. It is concluded that the most important function of the binding protein is that of a specific carrier, protecting the natural hormone against degradation by esterases. The carrier does not protect JH-I as efficiently as the lower homologue.}, language = {en} } @misc{PeterFoerster1989, author = {Peter, Martin G. and F{\"o}rster, Hans}, title = {On the structure of Eumelanins : identification of constitutional patterns by solid-state NMR spectroscopy}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17027}, year = {1989}, abstract = {Aus dem Inhalt: Melanins are complex polyphenolic polymers. They are usually formed in nature by enzyme-catalyzed oxidative polymerization of o-diphenols. The deep black eumelanins, derived from Dopa 1 or dopamine 3, are distinguished from the yellow to brown phaeomelanins obtained from Dopa in the presence of cysteine. Characteristic of eumelanins are the indole units, which are formed from catecholamines by intramolecular addition of the amino groups to the oxidatively generated o-quinones. [...]}, language = {en} } @article{WanjohiYenesewMidiwoetal.2005, author = {Wanjohi, John M. and Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G. and Dreyer, M. and Reichert, M. and Bringmann, Gerhard}, title = {Three dimeric anthracene derivatives from the fruits of Bulbine abyssinica}, issn = {0040-4020}, year = {2005}, abstract = {From the fruits of Bulbine abyssinica three new dimeric anthracene derivatives, (P)-8,9,1',8'- tetrahydroxy-3,3'-dimethyl[10,7'-bianthracene]-1,4,9',10'- tetraone (trivial name abyquinone A), (10R)-1,4,8,1',8-pentahydroxy-3,3'-dimethyl-[10,7'-bianthracene]9,9',10' (10H)-trione (trivial name abyquinone B), and (10R)-3,4'-dihydro-1,4,8,3',8',9'-hexahydroxy-3,3'- dimethyl-[10,7'-biant hracene]9,1'(10H,2'H)-dione (trivial name abyquinone Q were isolated. Despite their structural differences, these three compounds are connected to each other by the apparently biomimetic conversion of abyquinone C (a preanthraquinonylanthrone with two stereogenic centers) into B (an anthraquinonylanthrone with one stereogenic center) and finally into A (an axially chiral bianthraquinone) under mild conditions, involving a highly efficient center-to-axis chirality transfer. In addition, the known anthraquinones islandicin and chrysophanol were identified. The structures were determined on the basis of spectroscopical evidences, chemical transformations, and quantum chemical CD calculations. (C) 2005 Elsevier Ltd. All rights reserved}, language = {en} } @article{YenesewKiplagatDereseetal.2006, author = {Yenesew, Abiy and Kiplagat, John T. and Derese, Solomon and Midiwo, Jacob O. and Kabaru, Jacques M. and Heydenreich, Matthias and Peter, Martin G.}, title = {Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata}, doi = {10.1016/j.phytochem.2006.01.002}, year = {2006}, abstract = {The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone. (c) 2006 Elsevier Ltd. All rights reserved}, language = {en} } @article{YenesewMidiwoGuchuetal.2002, author = {Yenesew, Abiy and Midiwo, Jacob O. and Guchu, S. M. and Heydenreich, Matthias and Peter, Martin G.}, title = {Three iosoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii}, year = {2002}, abstract = {From the root bark of Erythrina burttii three new isoflav-3-enes, 7,4'-dihydroxy-2'-methoxy-6- (1'',1''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4'-hydroxy-2'- methoxy-(2'',2''-dimethylpyrano[5'',6'':8,7]isoflav-3-ene (trivial name, burttinol-B), 7,4'-dihydroxy-2'-methoxy-8-(3'',3''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-C), and a new 2-arylbenzofuran, 6,4'-dihydroxy-2'-methoxy-5- (1'',1''-dimethylallyl)-2-arylbenzofuran (trivial name, burttinol-D) were isolated. In addition, the known compounds, abyssinone V-4'-methyl ether, bidwillol A, calopocarpin, erybraedin A, erythrabyssin II, isobavachalcone, phaseollidin and phaseollin were identified. The structures were determined on the basis of spectroscopic evidence.}, language = {en} } @article{YenesewMushibeIndulietal.2005, author = {Yenesew, Abiy and Mushibe, E. K. and Induli, M. and Derese, Solomon and Midiwo, Jacob O. and Kabaru, Jacques M. and Heydenreich, Matthias and Koch, Andreas and Peter, Martin G.}, title = {7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoloata}, issn = {0031-9422}, year = {2005}, abstract = {From the acetone extract of the roots of Derris trifoliata an isollavonoid derivative, named 7a-O- methyldeguelol, a modified rotenoid with an open ring-C, representing a new sub-class of isollavonoids (the sub-class is here named as rotenoloid), was isolated and characterised. In addition, the known rotenoids, rotenone, deguelin and alpha-toxicarol, were identified. The structures were determined on the basis of spectroscopic evidence. Rotenone and deguelin were identified as the larvicidal principles of the acetone extract of the roots of Derris trifoliata. (c) 2005 Elsevier Ltd. All rights reserved}, language = {en} } @article{YenesewIrunguDereseetal.2003, author = {Yenesew, Abiy and Irungu, Beatrice and Derese, Solomon and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G.}, title = {Two prenylated flavonoids from the stem bark of Erythrina burttii}, year = {2003}, abstract = {From the stem bark of Erythrina burttii, a new isoflavone, 5,2',4'-trihydroxy-7-methoxy-6-(3- methylbut-2-enyl)isoflavone (trivial name, 7-O-methylluteone) and a new flavanone, 5,7-dihydroxy-4'-methoxy- 3'-(3-methylbutadienyl)-5'-(3-methylbut-2-enyl)flavanone (trivial name, burttinonedehydrate) along with three known isoflavonoids (8-prenylluteone, 3-O-methylcalopocarpin and genistein) were isolated. The structures were detd. on the basis of spectroscopic evidence.}, language = {en} } @article{YenesewMidiwoHeydenreichetal.2000, author = {Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Schanzenbach, Dirk and Peter, Martin G.}, title = {Two Isoflavanones from the Stem Bark of Erythrina sacleuxii}, year = {2000}, abstract = {From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2',4',5'- trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy- 2',4',5'-trimethoxy-2'',2''- dimethylpyrano[5'',6'':6,7]isoflavanone (trivial name, (R)-saclenone) were isolated. In addition the known compounds shinpterocarpin, 2,3-dehydrokievitone, abyssinone V, abyssinone V-4'-methyl ether, erythrinasinate and 4'-O-methylsigmoidin B were isolated. The structures were determined on the basis of spectroscopic evidence.}, language = {en} } @article{YenesewDereseMidiwoetal.2005, author = {Yenesew, Abiy and Derese, Solomon and Midiwo, Jacob O. and Bii, Christine C. and Heydenreich, Matthias and Peter, Martin G.}, title = {Antimicrobial flavonoids from the stem bark of Erythrina burttii}, issn = {0367-326X}, year = {2005}, abstract = {The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant. (c) 2005 Elsevier B.V. All rights reserved}, language = {en} } @phdthesis{DereseYenesewMidiwoetal.2003, author = {Derese, Solomon and Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G.}, title = {A new isoflavone from stem bark of Millettia dura}, issn = {1011-3924}, year = {2003}, language = {en} } @article{YenesewMidiwoMeisneretal.1998, author = {Yenesew, Abiy and Midiwo, Jacob O. and Meisner, M. and Heydenreich, Matthias and Peter, Martin G.}, title = {Two prenylated flavanones from stem bark of erythrina burttii}, year = {1998}, language = {en} } @article{YenesewMidiwoHeydenreichetal.1998, author = {Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G.}, title = {Four isoflavanones from stem bark of erythrina sacleuxii}, year = {1998}, language = {en} } @article{YenesewTwinomuhweziKiremireetal.2009, author = {Yenesew, Abiy and Twinomuhwezi, Hannington and Kiremire, Bernard T. and Mbugua, Martin N. and Gitu, Peter M. and Heydenreich, Matthias and Peter, Martin G.}, title = {8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica}, issn = {1011-3924}, year = {2009}, abstract = {A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone ext. of the root bark of Erythrina abyssinica. In addn., the known isoflavonoid derivs. eryvarin L, erycristagallin and shinpterocarpin were identified for the first time from the roots of this plant. The structures were detd. on the basis of spectroscopic evidence. The new compd. showed selective antimicrobial activity against Trichophyton mentagrophytes. The acetone ext. of the root bark of E. abyssinica showed radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the std. quercetin. [on SciFinder (R)]}, language = {en} } @article{RusuNgWilkeetal.2005, author = {Rusu, Viorel Marin and Ng, C. H. and Wilke, Max and Tiersch, Brigitte and Fratzl, Peter and Peter, Martin G.}, title = {Size-controlled hydroxyapatite nanoparticles as self-organized organic-in organic composite materials}, issn = {0142-9612}, year = {2005}, abstract = {This paper presents some results concerning the size-controlled hydroxyapatite nanoparticles obtained in aqueous media in a biopolymer matrix from soluble precursors salts. Taking the inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite was investigated. A stepwise co-precipitation approach was used to obtain different types of composites by means of different ratio between components. The synthesis of hydroxyapatite was carried out in the chitosan matrix from calcium chloride and sodium dihydrogenphosphate in alkaline solutions at moderate pH of 10-11 for 24 h. Our research is focused on studying and understanding the structure of this class of composites, aiming at the development of novel materials, controlled at the nanolevel scale. The X-ray diffraction technique was employed in order to study the kinetic of hydroxyapatite formation in the chitosan matrix as well as to determine the HAp crystallite sizes in the composite samples. The hydroxyapatite synthesized using this route was found to be nano-sized (15-50nm). Moreover, applying an original approach to analyze the (002) XRD diffraction peak profile of hydroxyapatite by using a sum of two Gauss functions, the bimodal distribution of nanosized hydroxyapatite within the chitosan matrix was revealed. Two types of size distribution domains such as cluster-like (between 200 and 400 nm), which are the habitat of "small" hydroxyapatite nanocrystallites and scattered-like, which are the habitat of "large" hydroxyapatite nanocrystallites was probed by TEM and CSLM. The structural features of composites suggest that self-assembly processes might be involved. The composites contain nanosized hydroxyapatite with structural features close to those of biological apatites that make them attractive for bone tissue engineering applications. (c) 2005 Elsevier Ltd. All rights reserved}, language = {en} } @misc{GrottPeterLinkeretal.2003, author = {Grott, Saskia and Peter, Martin G. and Linker, Torsten and Sefkow, Michael and Kroll, J{\"u}rgen and Koetz, Joachim and Laschewsky, Andr{\´e} and Lokatis, Siegfried and Rheinberg, Falko and Manig, Yvette}, title = {Portal = Chemie: Werkstoffe, Wirkstoffe, Lebensvorg{\"a}nge}, number = {01-02/2003}, organization = {Universit{\"a}t Potsdam, Referat f{\"u}r Presse- und {\"O}ffentlichkeitsarbeit}, issn = {1618-6893}, doi = {10.25932/publishup-43971}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439713}, pages = {46}, year = {2003}, abstract = {Aus dem Inhalt: - Chemie: Werkstoffe, Wirkstoffe, Lebensvorg{\"a}nge - Institut f{\"u}r Kirchenrecht gegr{\"u}ndet - Computerlinguisten erstellen digitales W{\"o}rterbuch - Vom Spaß am Graffiti-Sprayen}, language = {de} } @article{BringmannMutanyattaComarMaksimenkaetal.2008, author = {Bringmann, Gerhard and Mutanyatta-Comar, Joan and Maksimenka, Katja and Wanjohi, John M. and Heydenreich, Matthias and Brun, Reto and M{\"u}ller, Werner E. G. and Peter, Martin G. and Midiwo, Jacob O. and Yenesew, Abiy}, title = {Joziknipholones A and B : the first dimeric phenylanthraquinones, from the roots of Bulbine frutescens}, issn = {0947-6539}, year = {2008}, abstract = {From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P- configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells.}, language = {en} } @article{StruszczykPospiesznySchanzenbachetal.1998, author = {Struszczyk, Marcin Henryk and Pospieszny, Henryk and Schanzenbach, Dirk and Peter, Martin G.}, title = {Biodegradation of chitosan}, year = {1998}, language = {en} } @article{BerthDautzenbergPeter1998, author = {Berth, Gisela and Dautzenberg, Herbert and Peter, Martin G.}, title = {Physico-chemical characterization of chitosans varying in degree of acetylation}, issn = {0144-8617}, year = {1998}, language = {en} } @article{StruszczykLothKoehleretal.1998, author = {Struszczyk, Marcin Henryk and Loth, Fritz and K{\"o}hler, L. A. and Peter, Martin G.}, title = {Characterization of chitosan}, year = {1998}, language = {en} } @article{StruszczykLothPeter1998, author = {Struszczyk, Marcin Henryk and Loth, Fritz and Peter, Martin G.}, title = {Analysis of deacetylation deree in chitosans from various sources}, year = {1998}, language = {en} } @article{PeterWollenberger1997, author = {Peter, Martin G. and Wollenberger, Ursula}, title = {Phenol-oxidizing enzymes : mechanisms and applications}, year = {1997}, language = {en} } @article{BussVarumPeteretal.1996, author = {Buss, U. and Varum, K. M. and Peter, Martin G. and Spindler-Barth, Margarethe}, title = {ELISA for quantitation of chitin, chitosan and related compounds}, year = {1996}, language = {en} } @article{AndersenPeterRoepstorff1996, author = {Andersen, S. O. and Peter, Martin G. and Roepstorff, Peter}, title = {Cuticular sclerotization in insects}, year = {1996}, language = {en} } @article{KroeschePeter1996, author = {Kr{\"o}sche, Ch. and Peter, Martin G.}, title = {Detection of melanochromes by MALDI-TOF mass spectrometry}, year = {1996}, language = {en} } @article{LeyPeter1996, author = {Ley, J. P. and Peter, Martin G.}, title = {Synthesis of L-histidine and (-)-spinacine chitooligosyl amides}, year = {1996}, language = {en} } @article{LeyPeter1994, author = {Ley, J. P. and Peter, Martin G.}, title = {Synthesis of N-(2-Acetamido-2-deoxy-ß-D-glucopyranosyl)- and of N-(N,N-Diacetylchitobiosyl)-amide of lhistidine}, issn = {0039-7881}, year = {1994}, language = {en} } @article{PeterAndersen1994, author = {Peter, Martin G. and Andersen, S. O.}, title = {The molecular architecture of the insect exoskeleton}, year = {1994}, language = {en} } @article{SchumacherWanderslebPetersenPeter1994, author = {Schumacher-Wandersleb, Michael H. M. G. and Petersen, Stefan and Peter, Martin G.}, title = {Preparation of the N-Acetylglucosaminidase inhibitor 1-Acetamido-1,2,5-tride oxy-2,5-imino-D-glucitol from methyl a-D-Mannopyranoside}, year = {1994}, language = {en} } @article{HaebelPeterKatalinicPeter1997, author = {Haebel, Sophie and Peter-Katalinic, Jasna and Peter, Martin G.}, title = {Mass spectrometry of chitooligosaccharides}, isbn = {88-86889- 01-1}, year = {1997}, language = {en} } @article{CederkvistZamfirBahrkeetal.2006, author = {Cederkvist, F. Henning and Zamfir, Alina D. and Bahrke, Sven and Eijsink, Vincent G. H. and Sorlie, Morten and Peter-Katalinic, Jasna and Peter, Martin G.}, title = {Identification of a high-affinity-binding oligosaccharide by (+) nanoelectrospray quadrupole time-of-flight tandem mass spectrometry of a noncovalent enzyme-ligand complex}, issn = {1433-7851}, doi = {10.1002/anie.200503168}, year = {2006}, language = {en} } @article{MenezesGrigolonTodorovicetal.2009, author = {Menezes, Bruno M. and Grigolon, Lisanne and Todorovic, Zoran and Peter, Martin G. and Franco, Telma T.}, title = {On the depolymerization of chitosan by papain : a re-assessment}, year = {2009}, language = {en} } @article{FettkePeikowPeteretal.2009, author = {Fettke, Anja and Peikow, Dirk and Peter, Martin G. and Kleinpeter, Erich}, title = {Synthesis and conformational analysis of glycomimetic analogs of thiochitobiose}, issn = {0040-4020}, doi = {10.1016/j.tet.2009.03.067}, year = {2009}, abstract = {The synthesis of six analogs of N,N;-diacetylchitobiose is reported, including a novel transglycosylation reaction for the preparation of S-aryl thioglycosides. The conformations of the compounds were studied by a combination of NMR spectroscopy and molecular modeling, using force field calculations. In the case of the S-aryl thioglycosides with exclusively S-glycosidic linkages, dihedral angles of the disaccharidic S-glycosidic bonds, ;; and ;; and of the S-arylglycoside bonds, ; and ;, were found to be similar, whereas they were different in mixed glycosides and in a thiazoline derivative. An adequate correlation between the calculated H,H-distances of the local minima and the measured NOE contacts was achieved by applying population-weighted averages over participating conformers based on weighted relative energies.}, language = {en} } @article{OliveiraelGueddariMoerschbacheretal.2008, author = {Oliveira, Enio N. and el Gueddari, Nour E. and Moerschbacher, Bruno M. and Peter, Martin G. and Franco, Telma T.}, title = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides}, issn = {0301-486X}, year = {2008}, abstract = {Four phytopathogenic fungi were cultivated up to six days in media contg. chitooligosaccharide mixts. differing in av. DP and F A. The three different mixts. were named Q3 (which contained oligosaccharides of DP2-DP10, with DP2-DP7 as main components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixts. of oligosaccharides with different and known compn. on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concns. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concns. of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, resp. [on SciFinder (R)]}, language = {en} } @article{LondershausenTurbergBieseleretal.1996, author = {Londershausen, M. and Turberg, Andreas and Bieseler, Barbara and Lennarz, M. and Peter, Martin G.}, title = {Characterization and Inhibitor Studies of Chitinases from Parasitic Blowfly (Lucilia cuprina), Tick (Boophilus micoplus), Intestinale Nematode (Haemonchus contortus), and a Bean (Phaseolus vulgaris)}, year = {1996}, language = {en} } @article{LondershausenTurbergSpindlerBarthetal.1996, author = {Londershausen, M. and Turberg, Andreas and Spindler-Barth, Margarethe and Peter, Martin G.}, title = {Screening Test for Insecticides Interfering with Cuticular Sclerotization}, year = {1996}, language = {en} } @article{IssareeVijayakrishnanAbdelnuretal.2009, author = {Issaree, Arisara and Vijayakrishnan, Balakumar and Abdelnur, Patricia V. and Corilo, Yuri E. and Riccio, Maria F. and Sanvido, Gustavo B. and Eberlin, Marcos N. and Peter, Martin G.}, title = {Mass spectrometry of aminoglucan oligosaccharides using electrospray ionization MS/MS and MS/MS/MS}, year = {2009}, language = {en} } @article{StruszczykLothPeter1998, author = {Struszczyk, Marcin Henryk and Loth, Fritz and Peter, Martin G.}, title = {Calibration of methods for the determination of the degree of decatetylation of chitosan}, year = {1998}, language = {en} } @article{RawelKrollHaebeletal.1998, author = {Rawel, Harshadrai Manilal and Kroll, J{\"u}rgen and Haebel, Sophie and Peter, Martin G.}, title = {Reactions of a glucosinolate breakdown product (benzyl-isothiocyanate) with myoglobin}, year = {1998}, language = {en} } @article{PeterMiessner1997, author = {Peter, Martin G. and Miessner, Merle}, title = {Prim{\"a}rstoffwechsel, Shikimat- und Phenylpropan-Gruppe, Vitamine, Coenzyme, Pflanzeninhaltsstoffe}, year = {1997}, language = {de} } @article{RatajskaStruszczykBoryniecetal.1997, author = {Ratajska, M. and Struszczyk, Marcin Henryk and Boryniec, Stefan and Peter, Martin G. and Loth, Fritz}, title = {The degree of acetylation of chitosan : optimization of the IR Method}, year = {1997}, language = {en} } @article{SchanzenbachMaternPeter1997, author = {Schanzenbach, Dirk and Matern, Christa-Maria and Peter, Martin G.}, title = {Cleavage of chitin by means of sulfurice acid/acetc anhydride and isolation of peracetylated chito- oligosaccharides}, year = {1997}, language = {en} } @article{SchanzenbachPeter1997, author = {Schanzenbach, Dirk and Peter, Martin G.}, title = {NMR spectroscopy of chito-oligosaccharides}, year = {1997}, language = {en} } @article{SchanzenbachMaternPeter1997, author = {Schanzenbach, Dirk and Matern, Christa-Maria and Peter, Martin G.}, title = {Synthesis of glycosylamines and glycopeptides}, year = {1997}, language = {en} } @article{LeySchweikartPeter1997, author = {Ley, J. P. and Schweikart, F. and Peter, Martin G.}, title = {Chitinase inhibitors}, year = {1997}, language = {en} } @article{SchanzenbachPeter1997, author = {Schanzenbach, Dirk and Peter, Martin G.}, title = {Chromatography of chito-oligosaccarides}, year = {1997}, language = {en} } @article{Peter1995, author = {Peter, Martin G.}, title = {Applications and environmental aspects of chitin and chitosan}, issn = {0022-233X}, year = {1995}, language = {en} } @article{PeterLeyPetersenetal.1994, author = {Peter, Martin G. and Ley, J. P. and Petersen, Stefan and Londershausen, M. and Schumacher-Wandersleb, Michael H. M. G. and Spindler, Klaus-Dieter and Spindler-Barth, Margarethe and Turberg, Andreas}, title = {Synthesis of chitinase inhibitors}, year = {1994}, language = {en} } @article{KroescheCrescenziHoffbaueretal.1994, author = {Kr{\"o}sche, Christian and Crescenzi, Orlando and Hoffbauer, Wilfried and Jansen, Martin and Napolitano, Alessandra and Prota, Guiseppe and Peter, Martin G.}, title = {Synthesis of dopamines labelled with 13C in the alpha- or beta-side chain positions, and their application for structure studies on melanins by solid state NMR spectroscopy}, year = {1994}, language = {en} } @article{RukungaMuregiOmaretal.2008, author = {Rukunga, G. M. and Muregi, F. W. and Omar, S. A. and Gathirwa, J. W. and Muthaura, C. N. and Peter, Martin G.}, title = {Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus}, issn = {0367-326X}, year = {2008}, abstract = {Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.}, language = {en} } @article{StruszczykRatajskaBoryniecetal.1997, author = {Struszczyk, Marcin Henryk and Ratajska, M. and Boryniec, Stefan and Peter, Martin G. and Loth, Fritz}, title = {The determination of the degree of N-acetylation of chitosan}, year = {1997}, language = {en} } @article{HaebelBahrkePeter2007, author = {Haebel, Sophie and Bahrke, Sven and Peter, Martin G.}, title = {Quantitative sequencing of complex mixtures of heterochitooligosaccharides by vMALDI-linear ion trap mass spectrometry}, issn = {0003-2700}, doi = {10.1021/Ac062254u}, year = {2007}, abstract = {Heterochitooligosaccharides possess interesting biol. properties. Isobaric mixts. of such linear heterochitooligosaccharides can be obtained by chem. or enzymic degrdn. of chitosan. However, the sepn. of such mixts. is a challenging anal. problem which is so far unresolved. It is shown that these isobaric mixts. can be sequenced and quantified simultaneously using std. derivatization and multistage tandem mass spectrometric techniques. A linear ion trap mass spectrometer equipped with a vacuum matrix-assisted laser desorption ionization (vMALDI) source is used to perform MS2 as well as MS3 expts. [on SciFinder (R)].}, language = {en} } @article{StrefferKaatzBaueretal.1998, author = {Streffer, Katrin and Kaatz, Helvi and Bauer, Christian G. and Makower, Alexander and Schulmeister, Thomas and Scheller, Frieder W. and Peter, Martin G. and Wollenberger, Ursula}, title = {Application of a sensitive catechol detector for determination of tyrosinase inhibitors}, year = {1998}, language = {en} } @article{PeterKoehler1996, author = {Peter, Martin G. and K{\"o}hler, L. A.}, title = {Chitin und Chitosan : nachwachsende Rohstoffe aus dem Meer}, year = {1996}, language = {de} } @article{LopezFrancoCalderondelaBarcaValdezetal.2008, author = {L{\´o}pez-Franco, Yolanda L. and Calder{\´o}n de la Barca, Ana M. and Valdez, Miguel A. and Peter, Martin G. and Rinaudo, Marguerite and Chambat, G{\´e}rard and Goycoolea, Francisco M.}, title = {Structural characterization of mesquite (Prosopis velutina) gum and its fractions}, issn = {1616-5187}, doi = {10.1002/mabi.200700285}, year = {2008}, abstract = {Structural and physicochem. characteristics of mesquite gum (from Prosopis velutina) were investigated using FT- IR spectroscopic, mass spectrometric and chromatog. methods. Four fractions (F-I, F-IIa, F-IIb and F-III) were isolated by hydrophobic interaction chromatog. The samples were characterized and analyzed for their monosaccharide and oligomers compn. by high performance anion-exchange chromatog. with pulsed amperometric detection (HPAEC-PAD). L-Arabinose (L-Ara) and D-galactose (D-Gal) were found as the main carbohydrate constituent residues in the polysaccharides from mesquite gum and their ratio (L-Ara/D-Gal) varied within the range 2.54 to 3.06 among the various fractions. Small amts. of D- glucose (D-Glc), D-mannose (D-Man) and D-xylose (D-Xyl) were also detected, particularly in Fractions IIa, IIb and III. IR spectroscopy identified polysaccharides and protein in all the samples. Data from mass spectrometry (MALDI-TOF MS) was consistent with the idea that the structure corresponding to the periphereal chains of Fraction I is predominantly a chain of pentoses attached to uronic acid. [on SciFinder (R)].}, language = {en} } @article{TsukamotoHaebelValencaetal.2008, author = {Tsukamoto, Junko and Haebel, Sophie and Valenca, Gustavo P. and Peter, Martin G. and FRanco, Telma T.}, title = {Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides}, issn = {0268-2575}, year = {2008}, abstract = {Background: There is an increased need to replace materials derived from fossil sources by renewables. Sugar- cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the prepn. of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous prepn. of protected sugar derivs., such as glycosides, or activated acrylates, such as vinyl acrylate. Results: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of mol. sieves was investigated. The reactions were monitored by high-performance liq. chromatog. (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was obsd. for the D-glucose and D- fructose, followed by D-xylose and D-maltose. Mol. sieves had no pronounced effect on the conversion. Conclusions: A feasible method is described to produce and to characterize sugar acrylates, including those contg. more than two acrylate groups. The process for prodn. of these higher esters could potentially be optimized further to produce mols. for crosslinking in acrylate polymn. and other applications. The direct enzymic esterification of free carbohydrates with acrylic acid is unprecedented. [on SciFinder (R)].}, language = {en} } @article{NorledgeLambeirAbagyanetal.2001, author = {Norledge, Brian V. and Lambeir, Anne M. and Abagyan, Ruben and Rottmann, Antje and Fernendez, Anna M. and Filimonov, Vladimir V. and Peter, Martin G. and Wierenga, Rik K.}, title = {Modeling, mutagenesis, and structural studies on the fully conserved phoshate-binding loop (Loop 8) of triosephosphate isomerase : toward a new substrate specificity}, issn = {0887-2585}, year = {2001}, language = {en} } @article{AlarconAlderetePeteretal.1998, author = {Alarcon, Julio and Alderete, Joel B. and Peter, Martin G. and Becerra, Juan J. and Silva, M.}, title = {Study on synthesis of 3 alpha,4 alpha-dihydroxy-dihydro-beta-agarofuran}, year = {1998}, language = {en} } @article{SchumacherWanderslebPeter1995, author = {Schumacher-Wandersleb, Michael H. M. G. and Peter, Martin G.}, title = {Synthesis of chitobiosyl pyrrolidines}, year = {1995}, language = {en} } @article{AbegazPeter1995, author = {Abegaz, Berhanu M. and Peter, Martin G.}, title = {Emodine and emodinanthrone rhamnoside acetates from fruits of rhamnus prinoides}, issn = {0031-9422}, year = {1995}, language = {en} } @article{Peter1995, author = {Peter, Martin G.}, title = {The Bio-organic chemistry of melanogenesis}, year = {1995}, language = {en} } @article{Peter1995, author = {Peter, Martin G.}, title = {Chemie i Biochemia Zewnetrznego Szkieletu Owadow : (Chemistry and biochemistry of the insect exoskeleton)}, year = {1995}, language = {en} } @article{Peter1995, author = {Peter, Martin G.}, title = {Chemistry and biochemistry of the insect exoskeleton}, year = {1995}, language = {en} } @article{Peter1995, author = {Peter, Martin G.}, title = {Chitin in den Startl{\"o}chern}, issn = {0009-2959}, year = {1995}, language = {de} } @article{PeterMerz1995, author = {Peter, Martin G. and Merz, A.}, title = {Stereoselective benzylic deprotonation in the enzymatic rearrangement of N-acetyldopamine derived o-Quinone to the p-Quinone methide}, issn = {0957-4166}, year = {1995}, language = {en} } @article{EinarssonBahrkeSigurdssonetal.2013, author = {Einarsson, Jon M. and Bahrke, Sven and Sigurdsson, Bjarni Thor and Ng, Chuen-How and Petersen, Petur Henry and Sigurjonsson, Olafur E. and Jonsson, Halldor and Gislason, Johannes and Thormodsson, Finnbogi R. and Peter, Martin G.}, title = {Partially acetylated chitooligosaccharides bind to YKL-40 and stimulate growth of human osteoarthritic chondrocytes}, series = {Biochemical and biophysical research communications}, volume = {434}, journal = {Biochemical and biophysical research communications}, number = {2}, publisher = {Elsevier}, address = {San Diego}, issn = {0006-291X}, doi = {10.1016/j.bbrc.2013.02.122}, pages = {298 -- 304}, year = {2013}, abstract = {Recent evidences indicating that cellular kinase signaling cascades are triggered by oligomers of N-acetylglucosamine (ChOS) and that condrocytes of human osteoarthritic cartilage secrete the inflammation associated chitolectin YKL-40, prompted us to study the binding affinity of partially acetylated ChOS to YKL-40 and their effect on primary chondrocytes in culture. Extensive chitinase digestion and filtration of partially deacetylated chitin yielded a mixture of ChOS (Oligomin(TM)) and further ultrafiltration produced T-ChOS(TM), with substantially smaller fraction of the smallest sugars. YKL-40 binding affinity was determined for the different sized homologues, revealing micromolar affinities of the larger homologues to YKL-40. The response of osteoarthritic chondrocytes to Oligomin(TM) and T-ChOS(TM) was determined, revealing 2- to 3-fold increases in cell number. About 500 mu g/ml was needed for Oligomin(TM) and around five times lower concentration for T-ChOS(TM), higher concentrations abolished this effect for both products. Addition of chitotriose inhibited cellular responses mediated by larger oligosaccharides. These results, and the fact that the partially acetylated T-ChOS(TM) homologues should resist hydrolysis, point towards a new therapeutic concept for treating inflammatory joint diseases.}, language = {en} } @article{PereiraNascimentoMagalhaesetal.2014, author = {Pereira, Fernanda S. and Nascimento, Heliara D. L. and Magalhaes, Alvicler and Peter, Martin G. and Bataglion, Giovana Anceski and Eberlin, Marcos N. and Gonzalez, Eduardo R. P.}, title = {ESI(+)-MS and GC-MS study of the hydrolysis of N-azobenzyl derivatives of chitosan}, series = {Molecules}, volume = {19}, journal = {Molecules}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules191117604}, pages = {17604 -- 17618}, year = {2014}, abstract = {New N-p-chloro-, N-p-bromo-, and N-p-nitrophenylazobenzylchitosan derivatives, as well as the corresponding azophenyl and azophenyl-p-sulfonic acids, were synthesized by coupling N-benzylvchitosan with aryl diazonium salts. The synthesized molecules were analyzed by UV-Vis, FT-IR, H-1-NMR and N-15-NMR spectroscopy. The capacity of copper chelation by these materials was studied by AAS. Chitosan and the derivatives were subjected to hydrolysis and the products were analyzed by ESI(+)-MS and GC-MS, confirming the formation of N-benzyl chitosan. Furthermore, the MS results indicate that a nucleophilic aromatic substitution (SnAr) reaction occurs under hydrolysis conditions, yielding chloroaniline from N-p-bromo-, and N-p-nitrophenylazo-benzylchitosan as well as bromoaniline from N-p-chloro-, and N-p-nitrophenylazobenzyl-chitosan.}, language = {en} } @article{VijayakrishnanIssareeCoriloetal.2011, author = {Vijayakrishnan, Balakumar and Issaree, Arisara and Corilo, Yuri E. and Ferreira, Christina Ramires and Eberlin, Marcos N. and Peter, Martin G.}, title = {MSn of the six isomers of (GlcN)(2)(GlcNAc)(2) aminoglucan tetrasaccharides (diacetylchitotetraoses) rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides}, series = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, volume = {84}, journal = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2010.04.041}, pages = {713 -- 726}, year = {2011}, abstract = {The six possible isomers of di-N-acetylchitotetraoses [AADD, ADDA, ADAD, DADA, DAAD, and DDAA, where D stands for 2-amino-2-deoxy-3-D-glucose (GlcN) and A for 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc)] were analyzed by ESI(+)-MSn. Collision induced dissociation via MSn experiments were performed for the sodiated molecules of m/z 769 [M+Na](+) for each isomer, and fragments were generated mainly by glycosidic bond and cross-ring cleavages. Rules of fragmentation were then established. A reducing end D residue yields the (O.2)A(4) cross-ring [M-59+Na](+) fragment of m/z 710 as the most abundant, whereas isomers containing a reducing end A prefer to lose water to form the [M-18+Na](+) ion of m/z 751, as well as abundant (O.2)A(4) cross-ring [M-101+Na](+) fragments of m/z 668 and B-3 [M-221+Na](+) ions of m/z 548. MS3 of C- and Y-type ions shows analogous fragmentation behaviour that allows identification of the reducing end next-neighbour residue. Due to gas-phase anchimeric assistance, B-type cleavage between the glycosidic oxygen and the anomeric carbon atom is favoured when the glycon is an A residue. Relative ion abundances are generally in the order B >> C > Y, but may vary depending on the next neighbour towards the non-reducing end. These fragmentation rules were used for partial sequence analysis of hetero-chitooligosaccharides of the composition D(2)A(3), D(3)A(3), D(2)A(4), D(4)A(3), and D(3)A(4).}, language = {en} } @article{MengibarGananMirallesetal.2011, author = {Mengibar, M. and Ganan, M. and Miralles, B. and Carrascosa, A. V. and Martinez-Rodriguez, Adolfo J. and Peter, Martin G. and Heras, A.}, title = {Antibacterial activity of products of depolymerization of chitosans with lysozyme and chitosanase against Campylobacter jejuni}, series = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, volume = {84}, journal = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2010.04.042}, pages = {844 -- 848}, year = {2011}, abstract = {Chitosan has several biological properties useful for the food industry, but the most attractive is its potential use as a food preservative of natural origin due to its antimicrobial activity against a wide range of food-borne microorganisms. Among food-borne pathogens, Campylobacter jejuni and related species are recognised as the most common causes of bacterial food-borne diarrhoeal disease throughout the world. Recently, it has been demonstrated that campylobacters are highly sensitive to chitosan. Even though chitosan is known to have important functional activities, poor solubility makes them difficult to use in food and biomedical applications. Unlike chitosan, the low viscosity and good solubility of chitosan oligosaccharides (COS) make them especially attractive in an important number of useful applications. In the present work, the effect of different COS on C. jejuni was investigated. Variables such as the physicochemical characteristics of chitosan and the enzyme used in COS preparation were studied. The COS had been fractioned using ultrafiltration membranes and each fraction was characterized regarding its FA and molecular weight distribution. It has been demonstrated that the biological properties of COS on Campylobacter depend on the composition of the fraction analysed. COS prepared by enzymatic hydrolysis with chitosanase were more active against Campylobacter that lysozyme-derived COS, and this behaviour seems to be related with the acetylation of the chains. On the other hand. the 10-30 kDa fraction was the most active COS fraction, independently of the enzyme used for the hydrolysis. These results have shown that COS could be useful as antimicrobial in the control of C. jejuni.}, language = {en} } @article{FasciottiSanvidoSantosetal.2012, author = {Fasciotti, Maira and Sanvido, Gustavo B. and Santos, Vanessa G. and Lalli, Priscila M. and McCullagh, Michael and de Sa, Gilberto F. and Daroda, Romeu J. and Peter, Martin G. and Eberlin, Marcos N.}, title = {Separation of isomeric disaccharides by traveling wave ion mobility mass spectrometry using CO2 as drift gas}, series = {Journal of mass spectrometr}, volume = {47}, journal = {Journal of mass spectrometr}, number = {12}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1076-5174}, doi = {10.1002/jms.3089}, pages = {1643 -- 1647}, year = {2012}, abstract = {The use of CO2 as a massive and polarizable drift gas is shown to greatly improve peak-to-peak resolution (Rp-p), as compared with N2, for the separation of disaccharides in a Synapt G2 traveling wave ion mobility cell. Near or baseline Rp-p was achieved for three pairs of sodiated molecules of disaccharide isomers, that is, cellobiose and sucrose (Rp-p?=?0.76), maltose and sucrose (Rp-p?=?1.04), and maltose and lactose (Rp-p?=?0.74). Ion mobility mass spectrometry using CO2 as the drift gas offers therefore an attractive alternative for fast and efficient separation of isomeric disaccharides.}, language = {en} } @article{PazPeterSchmidtetal.2012, author = {Paz, Cristian and Peter, Martin G. and Schmidt, Bernd and Becerra, Jose and Gutierrez, Margarita and Astudillo, Luis and Silva, Mario}, title = {Synthesis and AChE inhibiting activity of 2, 4 substituted 6-Phenyl Pyrimidines}, series = {Journal of the Chilean Chemical Society}, volume = {57}, journal = {Journal of the Chilean Chemical Society}, number = {3}, publisher = {Sociedad Chilena De Quimica}, address = {Concepcion}, issn = {0717-9324}, pages = {1292 -- 1294}, year = {2012}, abstract = {Novel substituted pyrimidines were synthesized from methyl 2,4-dioxo-4-phenyl-butanoate (I-A) and urea, followed by Mitsunobu coupling of I-A with benzyl or allyl alcohol to give the corresponding 2-hydroxypyrimidine ethers in good yields. Saponification of I-A, followed by reaction with benzyl or allyl amines in the presence of TBTU yielded 2-hydroxy-6-phenyl-pyrimidine 4-carboxamides. AChE and BuChE assays revealed 2-hydroxy-6-phenyl-pyrimidine-4-carboxyallyamide as the most active compound, IC50=90 mu M, with no inhibition of BuChE.}, language = {en} } @article{GermerPeterKleinpeter2002, author = {Germer, Antje and Peter, Martin G. and Kleinpeter, Erich}, title = {Solution-state conformational study of the hevamine inhibitor allosamidin and six potential inhibitor analogues by NMR spectroscopy and molecular modeling}, year = {2002}, abstract = {The soln.-state conformations of the hevamine inhibitor allosamidin and six potential inhibitor analogs were studied by various NMR spectroscopic techniques and mol. modeling using force field calcns. Detn. solely of the global energy min. conformation was found to be insufficient for consensus with the NMR results, and agreement between the NMR exptl. data and the theor. calcns. was only reached by assessing the structures as population-weighted av. conformers on the basis of Boltzmann distributions derived from the calcd. relative energies. The conformations of the glycosidic linkages in the compds. were found to be similar when the sugar residues were the same, but differences were markedly evident otherwise and also for the various heterocyclic group linkages. The binding of the compds. to hevamine, which may also complex to chitinases in general, was assessed using HMQC, transfer-NOESY, and both 1-D and 2-D satn. transfer difference NMR expts. Under the conditions employed, only allosamidin was implicated to be bound to hevamine, and then only by HMQC with the dipolar coupling-based expts. failing to substantiate the formation of the complex. However, the results are consistent with the biochem. activities of the compds. whereby only allosamidin has been shown to act as a competitive inhibitor.}, language = {en} } @article{BahrkeEinarssonGislasonetal.2002, author = {Bahrke, Sven and Einarsson, Jon M. and Gislason, Johannes and Haebel, Sophie and Letzel, Matthias C. and Peter-Katalinic, Jasna and Peter, Martin G.}, title = {Sequence analysis of chitooligosaccharides by matrix-assisted laser desorption ionization postsource decay mass spectrometry}, year = {2002}, abstract = {Oligosaccharides composed of 2-acetamido-2-deoxy-D-glucopyranose (GlcNAc) and/or 2-amino-2-deoxy-D- glucopyranose (GlcN) were prepd. by chem. degrdn. of chitin or chitosan and sepd. by gel permeation chromatog. Oligosaccharides obtained after enzymic hydrolysis of chitosan [FA 0.19] with a fungal chitinase were derivatized by reductive amination with 2-aminoacridone and sequenced by matrix-assisted laser desorption ionization time-of-flight postsource decay (PSD) mass spectrometry (MS). The sequence of a trimer, D1A2, was established as D-A-A. The compn. of a hexamer D3A3 was .apprx.65\% D-A-D-D-A-A and 35\% D-D-A-D-A-A. The PSD MS of a nonamer D5A4-amac revealed four isobaric species D-X-Y-D-X-Y-D-A-A, where A is GlcNAc, D is GlcN, and X and Y (X ¹ Y) are mutually either D or A. This structure motif was also obsd. in a dodecamer D7A5 which was composed of eight isobaric sequences of the general formula (D-X-Y)3- D-A-A.}, language = {en} } @article{ThieleRottmannGermeretal.2002, author = {Thiele, Gabriela and Rottmann, Antje and Germer, Antje and Kleinpeter, Erich and Spindler, Klaus-Dieter and Synstad, Bjoenar and Eijsink, Vincent G. H. and Peter, Martin G.}, title = {Synthesis and conformational analysis of pseudosugar analogues of chitotriose}, year = {2002}, abstract = {In this article, the synthesis of analogs of N,N',N''-triacetylchitotriose in which the central sugar residue was replaced by a succinic acid is presented. Mol. modeling calcns. revealed that the pseudotrisaccharides exist in low energy extended conformations which show similar space filling as N,N',N''-triacetylchitotriose. Of the N,N',N''-triacetylchitotriose pseudosugar analogs tested as chitinase inhibitors, none showed any appreciable competition (numerical data not presented). The conformational anal. along with further synthetic efforts will hopefully lead to more efficient pseudosaccharides as chitinase inhibitors.}, language = {en} } @article{GermerKlodPeteretal.2002, author = {Germer, Antje and Klod, Sabrina and Peter, Martin G. and Kleinpeter, Erich}, title = {NMR spectroscopic and theoretical study of the complexation of the inhibitor allosamidin in the binding pocket of the plant chitinase hevamine}, year = {2002}, abstract = {Based on NMR spectroscopic information about the allosamidin-hevamine complex, ab initio MO calcns. of the ring current effect of the arom. moieties of Trp255, Tyr183 and Tyr6 of hevamine were carried out to investigate the role of these amino acid residues in binding interactions with allosamidin in soln. In addn., the intermol. steric compression effect on the 13C chem. shifts of the allosamizoline carbon atoms and the hydrogen bonding to Glu127 was identified. It can be inferred that the binding forces are strongest in the allosamizoline moiety of allosamidin.}, language = {en} } @article{HoustonShiomiAraietal.2002, author = {Houston, Douglas R. and Shiomi, Kazuro and Arai, Noriko and Omura, Satoshi and Peter, Martin G. and Turberg, Andreas and Synstad, Bjoenar and Eijsink, Vincent G. H. and Van Aalten, Daan M. F.}, title = {High-resolution structures of a chitinase complexed with natural product cyclopentapeptide inhibitors : mimicry of carbohydrate substrate}, year = {2002}, abstract = {Over the past years, family 18 chitinases have been validated as potential targets for the design of drugs against human pathogens that contain or interact with chitin during their normal life cycles. Thus far, only one potent chitinase inhibitor has been described in detail, the pseudotrisaccharide allosamidin. Recently, however, two potent natural-product cyclopentapeptide chitinase inhibitors, argifin and argadin, were reported. Here, we describe high- resoln. crystal structures that reveal the details of the interactions of these cyclopeptides with a family 18 chitinase. The structures are examples of complexes of a carbohydrate-processing enzyme with high-affinity peptide-based inhibitors and show in detail how the peptide backbone and side chains mimic the interactions of the enzyme with chitooligosaccharides. Together with enzymol. characterization, the structures explain why argadin shows an order of magnitude stronger inhibition than allosamidin, whereas argifin shows weaker inhibition. The peptides bind to the chitinase in remarkably different ways, which may explain the differences in inhibition consts. The two complexes provide a basis for structure-based design of potent chitinase inhibitors, accessible by std. peptide chem.}, language = {en} } @article{vanAaltenKomanderSynstadetal.2002, author = {van Aalten, Daan M. F. and Komander, David and Synstad, Bjoenar and Gaseidnes, Sigrid and Peter, Martin G. and Eijsink, Vincent G. H.}, title = {Structural Insights into the catalytic mechanism of a family 18 exochitinase}, year = {2002}, abstract = {Chitinase B (ChiB) from Serratia marcescens is a family 18 exochitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substrateassisted catalysis, and product displacement. The structure of an inactive ChiB mutant (E144Q) complexed with a pentameric substrate (binding in subsites 22 to 13) shows closure of the ''roof'' of the active site tunnel. It also shows that the sugar in the 21 position is distorted to a boat conformation, thus providing structural evidence in support of a previously proposed catalytic mechanism. The structures of the active enzyme complexed to Allosamidin (an analogue of a proposed reaction intermediate) and of the active enzyme soaked with pentameric substrate show events after cleavage of the glycosidic bond. The latter structure shows reopening of the roof of the active site tunnel and enzyme-assisted product displacement in the 11 and 12 sites, allowing a water molecule to approach the reaction center. Catalysis is accompanied by correlated structural changes in the core of the TIM barrel that involve conserved polar residues whose functions were hitherto unknown. These changes simultaneously contribute to stabilization of the reaction intermediate and alternation of the pKa of the catalytic acid during the catalytic cycle.}, language = {en} } @article{MiessnerPeterVincent2001, author = {Miessner, Merle and Peter, Martin G. and Vincent, Julian F. V.}, title = {Preparation of Insect-Cuticle-Like Biomimetic Materials}, year = {2001}, abstract = {A model system of tanning of a protein matrix within a fibrous structure, such as most commonly found in insect cuticle, was developed, using the cellulose of paper in place of chitin. The paper was impregnated with a tripeptide, DOPA-Gly-Gly, or a protein (BSA) plus catechol and treated with tyrosinase to oxidize the catechol. The resulting material was waterproof and had very high wet strength. If the material was wetted and dried repeatedly its water retention decreased by a factor of at least two.}, language = {en} } @article{Peter2001, author = {Peter, Martin G.}, title = {Nat{\"u}rliche Klebstoffe : von Muscheln, Seepocken, Spinnen und anderem Klebe-Getier}, isbn = {3-519-16195-8}, year = {2001}, language = {de} } @article{ZalaStruszczykPeter2001, author = {Zala, Eva and Struszczyk, Marcin Henryk and Peter, Martin G.}, title = {Effects of preparation methods for chitosan films on their properties}, year = {2001}, language = {en} } @article{StruszczykPospiesznySchanzenbachetal.2001, author = {Struszczyk, Marcin Henryk and Pospieszny, Henryk and Schanzenbach, Dirk and Peter, Martin G.}, title = {Biodegradation of various chitosans using Aspergillus fumigatus}, year = {2001}, language = {en} } @article{Peter2001, author = {Peter, Martin G.}, title = {Structures of Chitinases and the Design of Inhibitors}, year = {2001}, language = {en} } @article{LetzelPeterKatalinicPeter2001, author = {Letzel, Matthias C. and Peter-Katalinic, Jasna and Peter, Martin G.}, title = {Mass spectrometry of chitin and chitosan oligosaccharides}, year = {2001}, language = {en} } @article{StruszczykLothPospiesznyetal.2001, author = {Struszczyk, Marcin Henryk and Loth, Fritz and Pospieszny, Henryk and Peter, Martin G.}, title = {Biodegradation of films and paper sheets containing chitosan}, year = {2001}, language = {en} } @article{KamlageSefkowPeter2001, author = {Kamlage, Stefan and Sefkow, Michael and Peter, Martin G.}, title = {A short synthesis of biologically active lignan analogues}, year = {2001}, abstract = {beta-Benzyl-gamma-butyrolactones were synthesized in four transition metal catalysed reactions from butynediol, and alkylated to afford new, biologically active lignan analogues.}, language = {en} } @article{BeckerPeterPoolZobel2000, author = {Becker, Thomas W. and Peter, Martin G. and Pool-Zobel, Beatrice L.}, title = {Cellular effects of lignans : modulation of growth, oxidative DNA damage and cell metabolism in human colon cancer cells}, year = {2000}, language = {en} } @article{StruszczykLothPeter2000, author = {Struszczyk, Marcin Henryk and Loth, Fritz and Peter, Martin G.}, title = {Properties of microcrystalline chitosan gel-like dispersion and formed films}, year = {2000}, language = {en} } @article{RottmannSynstadEijsinketal.1999, author = {Rottmann, Antje and Synstad, Bjoenar and Eijsink, Vincent G. H. and Peter, Martin G.}, title = {Synthesis of N-acetylglucosaminyl and diacetylchitobiosyl amides of heterocyclic carboxylic acids as potential chitinase inhibitors}, year = {1999}, language = {en} }