β-GALACTOSIDASE OF PARACOLOBACTRUM AEROGENOIDES,

The occurrence of the enzyme ,B-galactosidase has been reported in a variety of microorganisms. As expected, the /8-galactosidases differ in their characteristics depending on the source. For example, Monod and Cohn (1952) have shown that the f3-galactosidases of Escherichia coli, Aerobacter aerogenes, and Shigella sonnei were indistinguishable from one another kinetically and serologically, but that the Saccharomyces fragilis and Lactobacillus bulgaricus ,B-galactosidases differed on the basis of these criteria from the E. coli enzyme. Recently Landman (1957) has shown that the /3-galactosidase produced by Bacillus megaterium is similar to the E. coli enzyme in its catalytic properties, but differs from it with respect to stability and serology. In this study the f,-galactosidase of Paracolobactrum aerogenoides is described and compared with the ,B-galactosidase of E. coli.