Purification and characterization of a CIostfidium perfringens α-galactosidase

Of 21 strains of C. perfringens tested for hydrolysis of α-galactosides, 10 utilized either raffinose or melibiose while 2 utilized both sugars. Spore production in Duncan Strong medium was superior in the presence of raffinose as opposed to starch in 12 out of 21 strains. C. perfringens M34 yielded 1.2 units of α-galactosidase/g washed cells. This enzyme had an isoelectric point of 5.6 and a pH optimum for hydrolysis of PNPG of 6.3. Native and monomer molecular weights were 96,000 and 46,000 daltons respectively. Km was 0.20 ± 0.02mM PNPG. Heat stability of the enzyme decreased as purity increased. This trend was partially reversed by addition of 2-mercaptoethanol, NADH, cysteine, and/or bovine serum albumin to reaction mixture.