TY - JOUR A1 - Abegaz, Berhanu M. A1 - Peter, Martin G. T1 - Emodine and emodinanthrone rhamnoside acetates from fruits of rhamnus prinoides Y1 - 1995 SN - 0031-9422 ER - TY - JOUR A1 - Alarcon, Julio A1 - Alderete, Joel B. A1 - Aguila, Sergio A1 - Peter, Martin G. T1 - Regio and stereoselective hydroxylation of alpha-agarofuran by biotransformation of rhizopus nigricans N2 - 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 Y1 - 2005 ER - TY - JOUR A1 - Alarcon, Julio A1 - Alderete, Joel B. A1 - Peter, Martin G. A1 - Becerra, Juan J. A1 - Silva, M. T1 - Study on synthesis of 3 alpha,4 alpha-dihydroxy-dihydro-beta-agarofuran Y1 - 1998 ER - TY - JOUR A1 - Andayi, Andrew W. A1 - Yenesew, Abiy A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Gitu, Peter M. A1 - Jondiko, Ogoche J. I. A1 - Akala, Hoseah M. A1 - Liyala, Pamela A1 - Wangui, Julia A1 - Waters, Norman C. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Antiplasmodial flavonoids from Erythrina sacleuxii N2 - The acetone extracts of the root bark and stem bark of Erythrina sacleuxii showed antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the acetone extract of the root bark afforded a new isoflavone, 7-hydroxy-4 -methoxy-3'- prenylisoflavone (trivial name 5-deoxy-3' - prenylbiochanin A) along with known isoflavonoids as the antiplasmodial principles. Flavonoids and isoflavonoids isolated from the stem bark of E. sucleuxii were also tested and showed antiplasmodial activities. The structures were determined on the basis of spectroscopic evidence Y1 - 2006 UR - http://www.thieme-connect.com/ejournals/toc/plantamedica U6 - https://doi.org/10.1055/s-2005-873200 SN - 0032-0943 ER - TY - JOUR A1 - Andersen, S. O. A1 - Peter, Martin G. A1 - Roepstorff, Peter T1 - Cuticular sclerotization in insects Y1 - 1996 ER - TY - JOUR A1 - Bahrke, Sven A1 - Einarsson, Jon M. A1 - Gislason, Johannes A1 - Haebel, Sophie A1 - Letzel, Matthias C. A1 - Peter-Katalinic, Jasna A1 - Peter, Martin G. T1 - Sequence analysis of chitooligosaccharides by matrix-assisted laser desorption ionization postsource decay mass spectrometry N2 - 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. Y1 - 2002 ER - TY - THES A1 - Bahrke, Sven A1 - Einarsson, Jon M. A1 - Gislason, Johannes A1 - Haebel, Sophie A1 - Peter-Katalinic, Jasna A1 - Peter, Martin G. T1 - Characterization of chitooligosaccharides by mass spectrometry Y1 - 2003 SN - 82-47-15901-5 ER - TY - JOUR A1 - Becker, Thomas W. A1 - Peter, Martin G. A1 - Pool-Zobel, Beatrice L. T1 - Cellular effects of lignans : modulation of growth, oxidative DNA damage and cell metabolism in human colon cancer cells Y1 - 2000 ER - TY - JOUR A1 - Berth, Gisela A1 - Dautzenberg, Herbert A1 - Peter, Martin G. T1 - Physica-chemical characterization of chitosans in dilute solution Y1 - 1998 SN - 2-907922-57-2 ER - TY - JOUR A1 - Berth, Gisela A1 - Dautzenberg, Herbert A1 - Peter, Martin G. T1 - Physico-chemical characterization of chitosans varying in degree of acetylation Y1 - 1998 SN - 0144-8617 ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Mutanyatta-Comar, Joan A1 - Maksimenka, Katja A1 - Wanjohi, John M. A1 - Heydenreich, Matthias A1 - Brun, Reto A1 - Müller, Werner E. G. A1 - Peter, Martin G. A1 - Midiwo, Jacob O. A1 - Yenesew, Abiy T1 - Joziknipholones A and B : the first dimeric phenylanthraquinones, from the roots of Bulbine frutescens N2 - 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. Y1 - 2008 UR - http://www3.interscience.wiley.com/journal/26293/home?CRETRY=1&SRETRY=0 SN - 0947-6539 ER - TY - JOUR A1 - Buss, U. A1 - Varum, K. M. A1 - Peter, Martin G. A1 - Spindler-Barth, Margarethe T1 - ELISA for quantitation of chitin, chitosan and related compounds Y1 - 1996 ER - TY - THES A1 - Derese, Solomon A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - A new isoflavone from stem bark of Millettia dura Y1 - 2003 SN - 1011-3924 ER - TY - JOUR A1 - Eijsink, Vincent G. H. A1 - Synstad, Bjoenar A1 - Gaseidnes, Sigrid A1 - Komander, David A1 - Houston, Douglas R. A1 - Peter, Martin G. A1 - van Aalten, Daan M. F. T1 - Structure and function of chitinolytic enzymes N2 - 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. Y1 - 2003 SN - 82-471-5901-5 ER - TY - JOUR A1 - Fasciotti, Maira A1 - Sanvido, Gustavo B. A1 - Santos, Vanessa G. A1 - Lalli, Priscila M. A1 - McCullagh, Michael A1 - de Sa, Gilberto F. A1 - Daroda, Romeu J. A1 - Peter, Martin G. A1 - Eberlin, Marcos N. T1 - Separation of isomeric disaccharides by traveling wave ion mobility mass spectrometry using CO2 as drift gas JF - Journal of mass spectrometr N2 - 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. KW - isomer resolution KW - oligosaccharides KW - traveling wave ion mobility mass spectrometry KW - polarizable drift gases Y1 - 2012 U6 - https://doi.org/10.1002/jms.3089 SN - 1076-5174 VL - 47 IS - 12 SP - 1643 EP - 1647 PB - Wiley-Blackwell CY - Hoboken ER - TY - GEN A1 - Ferenz, Hans-Jörg A1 - Peter, Martin G. T1 - The inhibitory effect of sinefungin on juvenile hormone biosynthesis and development in locusts N2 - The antibiotic fungal metabolite sinefungin is a potent inhibitor of S-adenosylmethionine-acceptor methyltransferases. Its effect on insect metabolism and especially on corpora allata farnesoic acid methyltransferase, which catalyzes the penultimate step of juvenile hormone biosynthesis, was investigated in Locusta migratoria. Injection of sinefungin results in a delay of imaginal molt and in suppression of ovary development. Isolated corpora allata are unable to synthesize juvenile hormone III in the presence of more than 1.0 mM sinefungin. In a cell-free system containing the S-adenosylmethionine-dependent farnesoic acid methyltransferase from corpora allata sinefungin is a competitive inhibitor of the synthesis of methylfarnesoate with Ki of 1 μM. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 076 KW - Locust KW - sinefungin KW - O-methyltransferase KW - juvenile hormone biosynthesis Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16811 ER - TY - GEN A1 - Ferenz, Hans-Jürgen A1 - Peter, Martin G. A1 - Berg, Dieter T1 - Inhibition of farnesoic acid methyltransferase by sinefungin N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 077 KW - Juvenile hormone analogue KW - Orthoptera KW - Juvenile hormone KW - Biosynthesis KW - Enzyme KW - Corpora allata KW - In vitro KW - Biological activity KW - Enzyme inhibitor Y1 - 1983 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17016 ER - TY - JOUR A1 - Fettke, Anja A1 - Peikow, Dirk A1 - Peter, Martin G. A1 - Kleinpeter, Erich T1 - Synthesis and conformational analysis of glycomimetic analogs of thiochitobiose N2 - 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. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00404020 U6 - https://doi.org/10.1016/j.tet.2009.03.067 SN - 0040-4020 ER - TY - JOUR A1 - Fotie, J. A1 - Nkengfack, A. E. A1 - Peter, Martin G. A1 - Heydenreich, Matthias A1 - Fomum, Z. T. T1 - Chemical constituents of the ethyl acetate extracts of the stem bark and fruits of Dichrostachys cinerea and the roots of Parkia bicolor N2 - 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 Y1 - 2004 SN - 1011-3924 ER - TY - JOUR A1 - Germer, Antje A1 - Klod, Sabrina A1 - Peter, Martin G. A1 - Kleinpeter, Erich T1 - NMR spectroscopic and theoretical study of the complexation of the inhibitor allosamidin in the binding pocket of the plant chitinase hevamine N2 - 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. Y1 - 2002 ER -