Abstract
Intracellular α-D-xylosidase from Penicillium wortmannii IFO 7237 was obtained by grinding the mold with almina in phosphate buffer, and the cell-free extract was purified to a homogeneous state on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight was estimated to be 290, 000 by gel filtration chromatography (Superdex 200) and 73, 000 was obtained by SDS-PAGE. The purified α-D-xylosidase had an isoelectric point at pH 5.0. The optimum activity for the enzyme was found to be at pH 6.5 and 45°C. The enzyme showed a hydrolytic activity on p-NO2-phenyl-α-D-xylopyranoside (α-p-NPX) while methyl-α-D-xylopyranoside (α-MX) was not hydrolyzed at all. It also showed lower activity for xyloglucan oligosacchdrides. The apparent Km values of the enzyme for α-p-NPX and isoprimeverose were 1.9 mM and 50 mM, respectively.
