Transfer Action of α-D-Xylosidases from Aspergillus flavus MO-5 on p-Nitrophenyl-α-D-xylopyranoside

概要

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The transfer action of α-D-xylosidase I and II from Aspergillus flavus MO-5 on p-nitrophenyl-α-D-xylopyranoside (α-p-NPX) was investigated, as compared with that of commercial α-D-xylosidase (from Bacillus sp.). In reaction mixtures with various concentrations of α-p-NPX, both enzymes (I and II) liberated p-nitrophenol and xylose at low concentrations, and showed transfer products in addition to hydrolyzates at high concentrations. IP-1 and IP-3, IIP-1 and IIP-2, and CP-1 and CP-3 were main transfer products by α-D-xylosidase I, α-D-xylosidase II, and commercial α-D-xylosidase, respectively. They were isolated by active charcoal column chromatography and silica gel column chromatography. Their structures were analyzed by enzymatic digestion, methylation analysis, and ^<13>C-NMR analysis. As the results, IP-1, IIP-2, and CP-1 were found to be the same structure, p-nitrophenyl-4-O-(α-D-xylopyranosyl)-α-D-xylopyranoside. Then, it was proved that the structure of IIP-1 was p-nitrophenyl-3-O-(α-D-xylopyranosyl)-α-xylopyranoside. On the other hand, IP-3 and CP-3 were found to be the same structure, D-xylopyranosyl-α-1,4-D-xylopyranose without a p-nitrophenyl group. We found that α-D-xylosidase I showed α-1,4 xylosyl transfer action as well as commercial α-D-xylosidase, and α-D-xylosidase II showed α-1,3 xylosyl transfer action in addition to α-1,4 xylosyl transfer action on α-p-NPX.
社団法人日本農芸化学会の論文
1994-01-23