Purification and characterization of alpha-L-rhamnosidase from Bacteroides JY-6, a human intestinal bacterium

An alpha-L-rhamnosidase (EC 3.2.1.40) was purified 1500-fold from Bacteroides JY-6, an intestinal anaerobic bacterium of human. The specific activity of purified enzyme was 89.9 mumol/min/mg protein. The enzyme (M.W. 240000) is composed of two subunits of M.W. 120000 with pI and optimal pH values of 4.2 and 7.0, respectively. The apparent Kms for naringin, rutin and p-nitrophenyl-alpha-L-rhamnopyranoside were determined to be 0.89, 1.44 and 0.29 mM, respectively. The enzyme was strongly inhibited by L-rhamnose, L-fucose, saccharic acid 1,4-lactone, p-chlormercuriphenylsulfonic acid and Pb2+.