CHARACTERIZATION OF ALPHA-GALACTOSIDASE FROM LACTOBACILLUS-FERMENTUM

alpha-Galactosidase activity was studied in Lactobacillus fermentum strains. The optimum temperature was found to be 45 degrees C. The enzyme was inactivated at temperatures higher than 55 degrees C, but remained active during storage at low temperatures (0, -30 and -70 degrees C) for 5 months. Enzyme activity was observed within a 5.0-6.5 pH range, while optimum pH was dependent on the particular strain assayed. The addition of Zn2+ to the reaction buffer exerted a slight negative effect upon the activity, while Hg2+ and p-chloromercuribenzoate produced a strong inhibition. These results would indicate the presence of -SH groups in the catalytic site of the enzyme.