Purification and characterization of bile salt hydrolase from Lactobacillus plantarum CK 102

Abstract

A bile salt hydrolase (BSH) was purified from Lactobacillus plantarum CK 102 and its enzymatic properties were characterized. This enzyme was successfully purified using ion-exchange chromatography with Q-Excellose and hydrophobic interaction chromatography with Butyl-Excellose. The purified enzyme showed a single protein band of 37 kDa by SDS-polyacrylamide gel electrophoresis, which was similar to the molecular weight of known BSHs. The amino acid sequence of GLGLPGDLSSMSR, determined by MALDI-TOF, was identical to that of BSH of L. plantarum WCFS 1. Although this BSH hydrolyzed all of the six major human bile salts, glycine-conjugated bile acid was the best substrate, based on its specificity and K m value. Among the various substrates, the purified enzyme maximally hydrolyzed glycocholate with apparent K m and V max values of 0.5 mM and 94 nmol/min/mg, respectively. The optimal pH of the enzyme ranged from 5.8 to 6.3. This enzyme was strongly inhibited by thiol enzyme inhibitors such as iodoacetate and periodic acid.