13088-77-2Relevant academic research and scientific papers
Catalytic Depolymerization of Chitin with Retention of N-Acetyl Group
Yabushita, Mizuho,Kobayashi, Hirokazu,Kuroki, Kyoichi,Ito, Shogo,Fukuoka, Atsushi
, p. 3760 - 3763 (2015/12/08)
Chitin, a polymer of N-acetylglucosamine units with β-1,4-glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N-acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N-acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N-acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical-force-assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short-chain oligomers. Subsequent hydrolysis of the ball-milled sample provided N-acetylglucosamine in 53 % yield, and methanolysis afforded 1-O-methyl-N-acetylglucosamine in yields of up to 70 %. Our process can greatly reduce the use of acid compared to the conventional process.
A glycosynthase derived from an inverting GH19 chitinase from the moss Bryum coronatum
Ohnuma, Takayuki,Fukuda, Tatsuya,Dozen, Satoshi,Honda, Yuji,Kitaoka, Motomitsu,Fukamizo, Tamo
, p. 437 - 443 (2012/09/25)
BcChi-A, a GH19 chitinase from the moss Bryum coronatum, is an endo-acting enzyme that hydrolyses the glycosidic bonds of chitin, (GlcNAc)n [a β-1,4-linked polysaccharide of GlcNAc (N-acetylglucosamine) with a polymerization degree of n], through an inverting mechanism. When the wild-type enzyme was incubated with α-(GlcNAc)2-F [α-(GlcNAc) 2 fluoride] in the absence or presence of (GlcNAc)2, (GlcNAc)2 and hydrogen fluoride were found to be produced through the Hehre resynthesis-hydrolysis mechanism. To convert BcChi-A into a glycosynthase, we employed the strategy reported by Honda et al. [(2006) J. Biol. Chem. 281, 1426-1431; (2008) Glycobiology 18, 325-330] of mutating Ser102, which holds a nucleophilic water molecule, and Glu 70, which acts as a catalytic base, producing S102A, S102C, S102D, S102G, S102H, S102T, E70G and E70Q. In all of the mutated enzymes, except S102T, hydrolytic activity towards (GlcNAc)6 was not detected under the conditions we used. Among the inactive BcChi-A mutants, S102A, S102C, S102G and E70G were found to successfully synthesize (GlcNAc)4 as amajor product from α-(GlcNAc)2-F in the presence of (GlcNAc) 2. The S102A mutant showed the greatest glycosynthase activity owing to its enhanced F- releasing activity and its suppressed hydrolytic activity. This is the first report on a glycosynthase that employs amino sugar fluoride as a donor substrate. The Authors Journal compilation
Enzymatic synthesis of 3-O-methylated chitin oligomers from new derivatives of a chitobiose oxazoline
Sakamoto, Junji,Kobayashi, Shiro
, p. 698 - 699 (2007/10/03)
Regiospecifically 3-O- and/or 3′-O-methylated derivatives of a chitobiose oxazoline have been synthesized as new substrate monomers and subjected to a chitinase catalysis, leading to the first synthesis of 3-O-methylated chitin oligomers via enzymatic oligomerization. (Graph Presented).
The amino acid sequence of satyr tragopan lysozyme and its activity
Araki, Tomohiro,Toshima, Gen,Kusao, Tomomi,Chijiiwa, Yuki,Kawamura, Shunsuke,Torikata, Takao
, p. 2621 - 2626 (2007/10/03)
The amino acid sequence of satyr tragopan lysozyme and its activity was analyzed. Carboxymethylated lysozyme was digested with trypsin and the resulting peptides were sequenced. The established amino acid sequence had three amino acid substitutions at positions 103 (Asn to Ser), 106 (Ser to Asn), and 121 (His to Gln) comparing with Temminck's tragopan lysozyme and five amino acid substitutions at positions 3 (Phe to Tyr), 15 (His to Leu), 41 (Gln to His), 101 (Asp to Gly) and 103 (Asn to Ser) with chicken lysozyme. The time course analysis using N-acetylglucosamine pentamer as a substrate showed a decrease of binding free energy change, 1.1 kcal/mol at subsite A and 0.2 kcal/mol at subsite B, between satyr tragopan and chicken lysozymes. This was assumed to be responsible for the amino acid substitutions at subsite A-B at position 101 (Asp to Gly), however another substitution at position 103 (Asn to Ser) considered not to affect the change of the substrate binding affinity by the observation of identical time course of satyr tragopan lysozyme with turkey and Temminck's tragopan lysozymes that carried the identical amino acids with chicken lysozyme at this position. These results indicate that the observed decrease of binding free energy change at subsites A-B of satyr tragopan lysozyme was responsible for the amino acid substitution at position 101 (Asp to Gly).
Glycosidase-catalysed Oligosaccharide Synthesis: Preparation of the N-Acetylchitooligosaccharides Penta-N-acetylchitopentaose and Hexa-N-acetylchitohexaose using the β-N-Acetylhexosaminidase of Aspergillus oryzae.
Singh, Suddham,Gallagher, Richard,Derrick, Peter J.,Crout, David H.G.
, p. 2803 - 2810 (2007/10/03)
Using a crude β-N-acetylhexosaminidase from Aspergillus oryzae both tri-N-acetylchitotriose (GlcNAc)3 (1,n=1) and tetra-N-acetylchitotetraose (GlcNAc4) (1,n=2) act respectively as both glycosyl donor and glycosyl acceptor to give product mixtures containing significant quantities of the corresponding penta- and hexasaccharides which are readily isolated and purified by charcoal-Celite chromatography.
THE BEHAVIOR OF CHITIN TOWARDS ANHYDROUS HYDROGEN FLUORIDE. PREPARATION OF β(1-4)-LINKED 2-ACETAMIDO-2-DEOXY-D-GLUCOPYRANOSYL OLIGOSACCHARIDES
Bosso, Claude,Defaye, Jacques,Domard, Alain,Gadelle, Andree,Pedersen, Christian
, p. 57 - 68 (2007/10/02)
Fluorohydrolysis of chitin in anhydrous hydrogen fluoride led to β-(1-4)-linked 2-acetamido-2-deoxy-D-glucopyranosyl oligosaccharides in almost quantitative yield.The average d.p. depended on both reaction time and temperature, and was conveniently monito
