English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Using possible monodeoxy derivatives of p-nitrophenyl (pNP) α-D-glucopyranoside, -mannopyranoside, and -galactopyranoside as probe substrate, glycon specificities of α-glucosidases, -mannosidases, and -galactosidases from various sources were investigated, through hydrolysis of them. α-Glucosidases of Saccharomyces cerevisiae, Bacillus stearothermophilus, and honeybee hydrolyzed no deoxy derivatives, while the enzymes of rice, sugar beet, flint corn, and Aspergillus (A.) niger hydrolyzed the 2-deoxy derivative with substantially high activities. Moreover, flint corn and A. niger enzymes showed, although low, activities against the 3-deoxy derivative. Jack bean and almond α-mannosidases both showed sufficient activities toward 6-deoxy derivative. A. niger α-galactosidase acted on only 2-deoxy derivative with substantially high activity, while the enzymes of green coffee bean and Mortierella vinacea hydrolyzed not only the 2-deoxy derivative but also 6-deoxy one with low activities. Oligosaccharides that contain 2- or 3-deoxygenated glucose were synthesized by the transesterification reaction of A. niger α-glucosidase. α- and β-Anomers of methyl 6-ο-(p-tolylsulfonyl)-D-glucopyranoside, -mannopyranoside, and -galactopyranoside were acetylated partially by lipase-catalyzed transesterification with vinyl acetate. A lipase from Pseudomonas cepacia (lipase PS) reveaed high activity and regioselectivity for the esterification of them.α-Glycopyranosides were acetylated preferentially at the C-2 hydroxyl group, while corresponding β-anomers were acetylated preferentially at the C-3 hydroxyl group. The best selectivity was observed in the reaction of the glucopyranosides. Using methyl 3-ο -acetyl-6-ο -(p-tolylsulfonyl)-β-Dglucopyranoside, which was prepared in quantitative yield by the lipase PS-catalyzed regioselective acetylation, as a common starting material, highly deoxygenated monosaccharides, namely 2, 6-dideoxy-D-arabino-hexopyranose, 2, 4-dideoxy-D-threo-hexopyranose, and 2, 4, 6-trideoxy-D-threo-hexopyranose, respectively, were chemically synthesized in good yields.

Effect of Sugar Hydroxyl Groups on Activities and Specificities of .ALPHA.-Glycosidase and Lipase.