CHEMICAL MODIFICATION OF BETA-GLUCOSIDASE BETA-FUCOSIDASE FROM DALBERGIA COCHINCHINENSIS-PIERRE BY CONDURITOL-B EPOXIDE/

Studies have been done on the inhibition and inactivation of the beta- glucosidase and beta-fucosidase enzyme from Thai Rosewood (Dalbergia c ochinchinesis Pierre). The enzyme was inhibited by Tris with similar K -i of 11.7 mM and 14.3 mM for the hydrolysis of p-nitrophenyl beta-D-g lucoside (PNPG) and p-nitrophenyl beta-D-fucoside (PNPF), respectively . Conduritol B epoxide inhibited both beta-glucosidase and beta-fucosi dase activities to similar extents, with a pseudo-first-order rate con stant (k(obs)) of inactivation of 5.56 x 10(-3) s(-1), and binding sto ichiometry of 0.9 mol per subunit. Partially inactivated enzyme showed similar kinetics with PNPG and PNPF as substrates. Moreover, Tris at 300 mM protected both beta-glucosidase and beta-fucosidase activities from inactivation by 6 mM CBE. The data support the idea that the Dalb ergia cochinchinensis Pierre enzyme has a common active site for the h ydrolysis of PNPG and PNPF.