Purification and some properties of .BETA.-xylosidase from Trichoderma viride.

Abstract

β-Xylosidase was purified 25 fold from a culture filtrate by ammonium sulfate fractionation, DEAE-Sephadex chromatography, column electrophoresis, gel filtration on Biogel P-100, and isoelectric focusing. The purified β-xylosidase was found to be homogeneous on SDS (sodium dodecyl sulfate) polyacrylamide gel electrophoresis and on disc electrophoresis. A molecular weight of 101,000 was estimated by chromatography on Sephadex G-200, and 102,000 was obtained by SDS polyacrylamide gel electrophoresis. The purified p-xylosidase had an isoelectric point at pH 4.45, and contained 4.5% carbohydrate residue. The optimum activity for the enzyme was found to be at pH 4.5 and 55°C. The enzyme activity was inhibited by Hg2 +, and N-bromosuccinimide at a concentration of 1 x 10−3 m. The purified enzyme hydrolyzed phenyl β-d-xyloside (ko—13.0 sec”1), p-nitrophenyl β-d-xyloside (ko=2l.3 sec−1), o-nitrophenyl β-d-xyloside (ko = 22.2 sec−1), o-chlorophenyl β-d-xyloside (ko = 20.0 sec−1), p-methylphenyl β-d-xyloside (ko~9....