HIGH-FIELD NMR-SPECTROSCOPY OF PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
.1. DETERMINATION OF THE DEGREE OF N-ACETYLATION AND THE DISTRIBUTION
OF N-ACETYL GROUPS IN PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
BY HIGH-FIELD NMR-SPECTROSCOPY
The composition and sequence of 2-acetamido-2-deoxy-beta-D-glucose
(GlcNAc) and 2-amino-2-deoxy-beta-D-glucose (GlcN) residues in partially
N-deacetylated chitosans, prepared under homogeneous and heterogeneous
conditions, have been determined by H-1-n.m.r. spectroscopy. It was
necessary to depolymerise the chitosan slightly by treatment with
nitrous acid before spectroscopy. A sequence-dependent deshielding
of H-1 of the GlcNAc residues made it possible to determine the proportions
of the four possible diads. Chitosan prepared by N-deacetylation
under homogeneous conditions gave values for the diad frequencies
that were roughly consistent with a random distribution of the N-acetyl
groups. Samples prepared under heterogeneous conditions have a frequency
of the GlcNAc-GlcNc diad slightly higher than for a random (Bernoullian)
distribution. The chitosans, prepared under both homogeneous and
heterogeneous conditions, with a degree of acetylation of 50% were
soluble at neutral pH.
%0 Journal Article
%1 VARUM1991a
%A VARUM, K. M.
%A ANTHONSEN, M. W.
%A GRASDALEN, H.
%A SMIDSROD, O.
%C PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
%D 1991
%I ELSEVIER SCIENCE BV
%J Carbohydr. Res.
%K ;; [ISI:] alginate h-1-nmr sequence; spectroscopy;
%N 1
%P 17 -- 23
%T HIGH-FIELD NMR-SPECTROSCOPY OF PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
.1. DETERMINATION OF THE DEGREE OF N-ACETYLATION AND THE DISTRIBUTION
OF N-ACETYL GROUPS IN PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
BY HIGH-FIELD NMR-SPECTROSCOPY
%V 211
%X The composition and sequence of 2-acetamido-2-deoxy-beta-D-glucose
(GlcNAc) and 2-amino-2-deoxy-beta-D-glucose (GlcN) residues in partially
N-deacetylated chitosans, prepared under homogeneous and heterogeneous
conditions, have been determined by H-1-n.m.r. spectroscopy. It was
necessary to depolymerise the chitosan slightly by treatment with
nitrous acid before spectroscopy. A sequence-dependent deshielding
of H-1 of the GlcNAc residues made it possible to determine the proportions
of the four possible diads. Chitosan prepared by N-deacetylation
under homogeneous conditions gave values for the diad frequencies
that were roughly consistent with a random distribution of the N-acetyl
groups. Samples prepared under heterogeneous conditions have a frequency
of the GlcNAc-GlcNc diad slightly higher than for a random (Bernoullian)
distribution. The chitosans, prepared under both homogeneous and
heterogeneous conditions, with a degree of acetylation of 50% were
soluble at neutral pH.
@article{VARUM1991a,
__markedentry = {[phpts:6]},
abstract = {The composition and sequence of 2-acetamido-2-deoxy-beta-D-glucose
(GlcNAc) and 2-amino-2-deoxy-beta-D-glucose (GlcN) residues in partially
N-deacetylated chitosans, prepared under homogeneous and heterogeneous
conditions, have been determined by H-1-n.m.r. spectroscopy. It was
necessary to depolymerise the chitosan slightly by treatment with
nitrous acid before spectroscopy. A sequence-dependent deshielding
of H-1 of the GlcNAc residues made it possible to determine the proportions
of the four possible diads. Chitosan prepared by N-deacetylation
under homogeneous conditions gave values for the diad frequencies
that were roughly consistent with a random distribution of the N-acetyl
groups. Samples prepared under heterogeneous conditions have a frequency
of the GlcNAc-GlcNc diad slightly higher than for a random (Bernoullian)
distribution. The chitosans, prepared under both homogeneous and
heterogeneous conditions, with a degree of acetylation of 50% were
soluble at neutral pH.},
added-at = {2011-11-04T13:47:04.000+0100},
address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
author = {VARUM, K. M. and ANTHONSEN, M. W. and GRASDALEN, H. and SMIDSROD, O.},
biburl = {https://www.bibsonomy.org/bibtex/2de773d13164f738dcdc305fa4fb2fb05/pawelsikorski},
citedref = {ALLAN GG, 1989, CHITIN CHITOSAN, P443 ; BOCK K, 1982, ANNU REP NMR
SPECTRO, V13, P1 ; GRASDALEN H, 1979, CARBOHYD RES, V68, P23 ; GRASDALEN
H, 1980, CARBOHYD RES, V81, P59 ; GRASDALEN H, 1981, CARBOHYD RES,
V89, P179 ; GRASDALEN H, 1983, CARBOHYD RES, V118, P255 ; GRASDALEN
H, 1988, CARBOHYD RES, V184, P183 ; HACKMAN RH, 1954, AUSTRALIAN
J BIOL SC, V7, P168 ; KNORR D, 1986, PROCESS BIOCHEM, V21, P90 ;
KURITA K, 1977, MAKROMOL CHEM, V178, P3197 ; MOORE GK, 1980, INT
J BIOL MACROMOL, V2, P115 ; MUZZARELLI RAA, 1986, CHITIN NATURE TECHNO,
P385 ; NEUGEBAUER WA, 1989, CARBOHYD RES, V189, P363 ; SANNAN T,
1976, MAKROMOL CHEM, V177, P3589 ; SANNAN T, 1978, POLYMER, V19,
P458 ; TERRASSIN C, 1986, THESIS I NATIONAL PO},
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intrahash = {de773d13164f738dcdc305fa4fb2fb05},
isifile-dt = {Article},
isifile-ga = {FL628},
isifile-j9 = {CARBOHYD RES},
isifile-nr = {16},
isifile-pi = {AMSTERDAM},
isifile-rp = {VARUM, KM, UNIV TRONDHEIM,NORWEGIAN INST TECHNOL,DIV ; BIOTECHNOL,NORWEGIAN
BIOPOLYMER LAB,N-7034 TRONDHEIM,NORWAY.},
isifile-sc = {Biochemistry & Molecular Biology; Chemistry, Applied; Chemistry, Organic},
isifile-tc = {151},
issn = {0008-6215},
journal = {Carbohydr. Res.},
keywords = {;; [ISI:] alginate h-1-nmr sequence; spectroscopy;},
language = {English},
month = {APR 2},
number = 1,
owner = {phpts},
pages = {17 -- 23},
publisher = {ELSEVIER SCIENCE BV},
size = {7 p.},
sourceid = {ISI:A1991FL62800002},
timestamp = {2011-11-04T13:47:27.000+0100},
title = {HIGH-FIELD NMR-SPECTROSCOPY OF PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
.1. DETERMINATION OF THE DEGREE OF N-ACETYLATION AND THE DISTRIBUTION
OF N-ACETYL GROUPS IN PARTIALLY N-DEACETYLATED CHITINS (CHITOSANS)
BY HIGH-FIELD NMR-SPECTROSCOPY},
volume = 211,
year = 1991
}