Purification and some properties of cyclo(Gly-Gly) hydrolase from a strain of Bacillus sp. No. 106.

Abstract

Bacillus sp. No. 106, which was isolated from soil, secreted an enzyme that hydrolyzed cyclo(Gly-Gly). The enzyme was purified to the ultracentrifugally homogeneous state and an activity more than 450-fold that of culture broth. The enzyme was activated by Na+, Mg2+, Ca2+, and Sr2+, and strongly inhibited by Ni2+, Cu2+, p-chloromercuribenzoate, and monoiodoacetic acid. The Km value for cyclo(Gly-Gly) was estimated to be 11.1 mM. The enzyme hydrolyzed only cyclo(Gly-Gly) among various diketopiperazines tested. Aslo, the enzyme was inert toward Gly-Gly, milk casein, and hemoglobin.