TY  - JOUR
A1  - Vijayakrishnan, Balakumar
A1  - Issaree, Arisara
A1  - Corilo, Yuri E.
A1  - Ferreira, Christina Ramires
A1  - Eberlin, Marcos N.
A1  - Peter, Martin G.
T1  - 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
JF  - Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides
N2  - 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).
KW  - Chitosan
KW  - Fragmentation
KW  - Oligosaccharides
KW  - Sequence analysis
KW  - Tandem mass spectrometry
Y1  - 2011
U6  - https://doi.org/10.1016/j.carbpol.2010.04.041
SN  - 0144-8617
VL  - 84
IS  - 2
SP  - 713
EP  - 726
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Issaree, Arisara
A1  - Vijayakrishnan, Balakumar
A1  - Abdelnur, Patricia V.
A1  - Corilo, Yuri E.
A1  - Riccio, Maria F.
A1  - Sanvido, Gustavo B.
A1  - Eberlin, Marcos N.
A1  - Peter, Martin G.
T1  - Mass spectrometry of aminoglucan oligosaccharides using electrospray ionization MS/MS and MS/MS/MS
Y1  - 2009
ER  - 
TY  - THES
A1  - Issaree, Arisara
T1  - Synthesis of Hetero-chitooligosaccharides
T1  - Synthese von Hetero-Chitooligosacchariden
N2  - Chitooligosaccharides are composed of linear β-(1→4)-linked 2-acetamido-2-deoxy-β-D-glucopyranose (GlcNAc) and/or 2-amino-2-deoxy-β-D-glucopyranose (GlcN). They are of interest due to their remarkable biological properties including antibacterial, antitumor, antifungal and elicitor activities. They can be obtained from the aminoglucan chitosan by chemical or enzymatic degradation which obviously affords rather heterogenous mixtures. On the other hand, chemical synthesis provides pure compounds with defined sequences of GlcNAc and GlcN monomers. The synthesis of homo- and hetero-chitobioses and hetero-chitotetraoses is described in this thesis. Dimethylmaleoyl and phthaloyl groups were used for protection of the amines. The donor was activated as the trichloroacetimidate in order to form the β-linkages. Glycosylation in the presence of trimethylsilyl trifluoromethanesulfonate, followed by N- and O-deprotection furnished chitobioses and chitotetraoses in good yields.
N2  - Chitooligosacchride bestehen aus linear β-(1→4)-verknüpften 2-acetamido-2-deoxy-β-D-glucopyranose (GlcNAc) and/or 2-amino-2-deoxy-β-D-glucopyranose (GlcN) Einheiten. Sie beanspruchen aufgrund ihrer bemerkenswerten biologischen Eigenschaften – u.a. antibakterielle, antitumor, antimykotische und Elicitor Aktivität - grosses Interesse. Sie sind durch chemischen oder enzymatischen Abbau von Chitosan zugänglich, wobei diese Methoden unausweichlich zu komplexen, sehr heterogenen Mischungen von Chiooligosacchariden führen. Chemische Synthesen von Chitooligosacchariden mit definierter Sequenz von GlcNAc und GlcN Einheiten sind daher von erheblichem Interesse. In der vorliegenden Arbeit werden Synthesen von partiell acetylierten Chitobiosen und –tetraosen beschrieben. Die Aminogruppen wurden als N-Dimethylmaleoyl- bzw. Phthaloylimide geschützt. Die Donoren wurden als Trichloacetimidate aktiviert, wobei aufgrund von Nachbargruppeneffekten ausschliesslich die β-Glycoside entstehen. Die Trimethylsilyltrifluoromethansulfonat-promovierte Glycosidierung geeigneter Akzeptoren lieferte schliesslich die Chitobiosen und die Chitotetraosen in guten Ausbeuten.
KW  - Kohlenhydrate
KW  - Chitooligosaccharide
KW  - Glycosylierung
KW  - Synthesemethoden
KW  - Trichloracetimidate
KW  - Carbohydrates
KW  - Chitooligosaccharides
KW  - Glycosylation
KW  - Synthetic methods
KW  - Trichloroacetimidates
Y1  - 2008
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17069
ER  -