C-2 Epimerization of Disaccharides by Calcium(II)–Monoamine Systems. A Direct Synthesis of (1→4)-Linked Disaccharides Having a D-Mannose Unit as a Reducing Terminal
The acceptor specificity of amylomaltase from Eschenchia coli IFO 3806 was investigated using various sugars and sugar alcohols. D-Mannose, D-glucosamine, N-acetyl-D-glucosamine, D-xylose, D-allose, isomaltose, and cellobiose were efficient acceptors in the transglycosylation reaction of this enzyme. It was shown by chemical and enzymic methods that this enzyme could transfer glycosyl residues only to the C4-hydroxyl groups of D-mannose, N-acetyl-D-glucosamine, D-allose, and D-xylose, producing oligosaccharides terminated by 4-O-α-D-glucopyranosyl-D-mannose, 4-O-α-D-glucopyranosyl-N-acetyl-D-glucosamine, 4-O-α-D-glucopyranosyl-D-allose, and 4-O-α-D-glucopyranosyl-D-xylose at the reducing ends, respectively.
(1→6)-Linked disaccharides having mannose as a reducing unit were synthesized from their naturally abundant C-2 epimers by the novel C-2 epimerization promoted by nickel(II)-diamine complex, [Ni(H2O)2(tmen)2]Cl2 (tmen = N,N,N′-trimethylethylenediamine).
Kinetics of alkaline degradation of maltose in ethanol-water solutions
作者:Tapani Vuorinen
DOI:10.1016/s0008-6215(00)81791-7
日期:1982.10
Abstract The kinetics of the alkalinedegradation of maltose in solution in 0.1 m sodium hydroxide in ethanol-water of up to 53% (w/w) concentration of ethanol were studied over a temperature range of 30–60°. The isomerization of maltose to maltulose and its further degradation proceeded at approximately the same rate, whereas the isomerization of maltulose to maltose was significantly slower. All
Efficient one-pot enzymatic synthesis of α-(1→4)-glucosidic disaccharides through a coupled reaction catalysed by Lactobacillus acidophilus NCFM maltose phosphorylase
Lactobacillus acidophilus NCFM maltose phosphorylase (LaMalP) of glycoside hydrolase family 65 catalysed enzymatic synthesis of alpha-(1 -> 4)-glucostdic disacchandes from maltose and five monosacchandes in a coupled phosphorolysis/reverse phosphorolysis one-pot reaction Thus phosphorolysis of maltose to 0-glucose I -phosphate circumvented addition of costly 0-glucose 1-phosphate for reverse phosphorolysis with different monosacchande acceptors, resulting in 91%, 89%, 88%, 86% and 84% yield of alpha-a-glucopyranosyl-(1 4)-N-acetyl-a-glucosain inopyranose IN-acetyl-maltosamine I, alpha-b-glucopyranosyl( 1 -> 4)-o-glucosaminopyranose I maltosaminej, a-a-glucopyranosyl-(1 -> 4)-b-mannopyranose, alpha-n-glucopyranosyl-(1 -> 4)-t-fucopyranose and alpha-b-glucopyranosyl-(1 -> 4)-D-xylopyranose, respectively, from 0 1 M maltose, 0.5 M N-acetyl glucosamine, 0.1 M glucosamine. 0.1 M mannose, 1 M t-fucose and 0.5 M xylose in 02 M phosphate-citrate p1-I 62 These current yields of 0.27-0.34 g of disaccharide products from 10 mL reaction mixtures are easy to scale up and moreover the strategy can be applied to large-scale production of other oligosacchandes from low-cost disacchandes as catalysed by phosphorylases with different substrate specificities 2010 Elsevier Ltd All rights reserved.