%0 Journal Article %1 Tommeraas2001 %A Tommeraas, K. %A Varum, K. M. %A Christensen, B. E. %A Smidsrod, O. %C THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND %D 2001 %I ELSEVIER SCI LTD %J Carbohydr. Res. %K ; ;; C-13 H-1 MALDI-TOF MS NMR; [ISI:] acid; c-13-nmr; chitins chitosan; chitosans; chromatography; deacetylated depolymerisation; field h-1-nmr; lysozyme n-acetylation; nitrous nmr-spectroscopy; size-exclusion %N 2 %P 137 -- 144 %T Preparation and characterisation of oligosaccharides produced by nitrous acid depolymerisation of chitosans %V 333 %X Two chitosans with widely different chemical composition (fraction of N-acetylated units (F-A)<0.001 and F-A= 0.59), were degraded by nitrous acid, to obtain the reactive 2,5-anhydro-D-mannose- (M-) unit at the new reducing end. The fully N-acetylated and fully N-deacetylated oligomers were separated by size-exclusion chromatography. Both the chemical structure and purity were studied by one- and two-dimensional H-1 and C-13 NMR methods. The fully N-acetylated oligomers were found to be stable, whereas the N-deacetylated oligomers reacted intermolecularly by a Schiff base reaction between the 2-amino group on the N-deacetylated units and the M-units, facilitating the cleavage of the glycosidic bond next to the M-unit and the formation of 5-hydroxymethylfurfural (HMF). (C) 2001 Elsevier Science Ltd. All rights reserved.

@article{Tommeraas2001, __markedentry = {[phpts:6]}, abstract = {Two chitosans with widely different chemical composition (fraction of N-acetylated units (F-A)<0.001 and F-A= 0.59), were degraded by nitrous acid, to obtain the reactive 2,5-anhydro-D-mannose- (M-) unit at the new reducing end. The fully N-acetylated and fully N-deacetylated oligomers were separated by size-exclusion chromatography. Both the chemical structure and purity were studied by one- and two-dimensional H-1 and C-13 NMR methods. The fully N-acetylated oligomers were found to be stable, whereas the N-deacetylated oligomers reacted intermolecularly by a Schiff base reaction between the 2-amino group on the N-deacetylated units and the M-units, facilitating the cleavage of the glycosidic bond next to the M-unit and the formation of 5-hydroxymethylfurfural (HMF). (C) 2001 Elsevier Science Ltd. All rights reserved.}, added-at = {2011-11-04T13:47:04.000+0100}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, author = {Tommeraas, K. and Varum, K. M. and Christensen, B. E. and Smidsrod, O.}, authoraddress = {Norwegian Univ Sci & Technol, Dept Biotechnol, Norwegian Biopolymer Lab, NOBIPOL,NTNU, N-7491 Trondheim, Norway.}, biburl = {https://www.bibsonomy.org/bibtex/2e9f931c0491c7e23bc5249bf6f3b4a48/pawelsikorski}, citedref = {ALLAN GG, 1989, CHITIN CHITOSAN, P443 ; AMES JM, 1992, MAILLARD REACTION BI ; ANTHONSEN MW, 1993, THESIS NORWEGIAN I T ; ANTHONSEN MW, 1995, CARBOHYD POLYM, V26, P303 ; BELITZ HD, 1999, FOOD CHEM ; BOYD J, 1985, CARBOHYD RES, V139, P35 ; DEROME AE, 1987, MODERN NMR TECHNIQUE ; DOMARD A, 1987, INT J BIOL MACROMOL, V9, P98 ; DOMARD A, 1991, INT J BIOL MACROMOL, V13, P105 ; FENNEMA OR, 1985, FOOD CHEM ; FREEMAN R, 1978, J CHEM SOC CHEM COMM, P684 ; GOTTSCHALK A, 1952, BIOCHEM J, V52, P455 ; HACKMAN RH, 1954, AUSTRALIAN J BIOL SC, V7, P168 ; HAYASHI T, 1986, ROLE SUGAR FRAGMENTA, V13 ; ISHIGURO K, 1992, CARBOHYD RES, V237, P333 ; MANINI P, 1999, BIOORGAN MED CHEM, V7, P2525 ; NILGES M, 1991, J MOL BIOL, V219, P499 ; ROBERTS GAF, 1992, CHITIN CHEM ; SANNAN T, 1976, MAKROMOL CHEM, V177, P3589 ; SASHIWA H, 1993, CARBOHYD RES, V242, P167 ; VARUM KM, 1991, CARBOHYD RES, V211, P17 ; VARUM KM, 1991, CARBOHYD RES, V217, P19 ; WISHART DS, 1995, J BIOMOL NMR, V6, P135}, interhash = {fc0dae532635c0235f0eee15da9e19e4}, intrahash = {e9f931c0491c7e23bc5249bf6f3b4a48}, isifile-dt = {Article}, isifile-ga = {454LE}, isifile-j9 = {CARBOHYD RES}, isifile-nr = {23}, isifile-pi = {OXFORD}, isifile-rp = {Tommeraas, K, Norwegian Univ Sci & Technol, Dept Biotechnol, Norwegian ; Biopolymer Lab, NOBIPOL,NTNU, N-7491 Trondheim, Norway.}, isifile-sc = {Biochemistry & Molecular Biology; Chemistry, Applied; Chemistry, Organic}, isifile-tc = {14}, issn = {0008-6215}, journal = {Carbohydr. Res.}, keywords = {; ;; C-13 H-1 MALDI-TOF MS NMR; [ISI:] acid; c-13-nmr; chitins chitosan; chitosans; chromatography; deacetylated depolymerisation; field h-1-nmr; lysozyme n-acetylation; nitrous nmr-spectroscopy; size-exclusion}, language = {English}, month = {JUL 3}, number = 2, owner = {phpts}, pages = {137 -- 144}, publisher = {ELSEVIER SCI LTD}, size = {8 p.}, sourceid = {ISI:000169973400006}, timestamp = {2011-11-04T13:47:26.000+0100}, title = {Preparation and characterisation of oligosaccharides produced by nitrous acid depolymerisation of chitosans}, volume = 333, year = 2001 }