Purification and characterization of 6-phospho-beta-galactosidase from Lactobacillus gasseri JCM 1031

6-Phospho-beta-galactosidase from Lactobacillus gasseri JCM 1031 was purified from lactobacilli to homogeneity, about 118-fold, with 0.5% recovery by several chromatographies. The molecular mass and isoelectric point of the purified enzyme were 58 kDa and pI 5.5, respectively. The Km and Vmax for o-nitrophenyl-beta-D-galactopyranoside-6-phosphate were 0.8 mM and 116.4 mumol/min/mg, respectively. Reducing agent, Fe2+ ion, and EDTA activated but PCMB, Zn2+, and Hg2+ ions strongly inhibited the enzymatic activity.