BETA-XYLOSIDASE FROM LIVER OF CHARONIA LAMPAS .2. BETA-XYLOSIDASE AND BETA-GLUCOSIDASE

1. The consideration that the both activities of β-xyIosidase [EC 3.2.1.37] and β-glucosidase in the purified enzyme preparation from Charonia lampas are due to a single enzyme was further supported by kinetic experiments, including inhibition test and analysis of reaction using two substrates.2. The properties of both activities were studied: pH optimum for both activities is pH4.0: Km for p-nitrophenyl β-D-xyloside is 2.31 mM and for p-nitrophenyl β-D-glucoside 2.08 mM; K1 of xylose for p-nitrophenyl β-D-xyloside and p-nitrophenyl β-D-glucoside are 3.9 and 3.3 mM and that of glucose for p-nitrophenyl β-D-xyloside and p-nitro-phenyl β-D-glucoside are 2.5 and 2.3 mM, respectively. Mannose did not inhibit either activity at all.3. The existence of β-glucosidase [EC 3.2.1.21] which contains no or little β-xylosidase activity was also detected by column chromatography. © 1969 BY THE JOURNAL OF BIOCHEMISTRY.