γ-Polyglutamic Acid Depolymerase Induced by Infections of natto and subtilis Phages and Its Further Properties

Abstract

The known B. subtilis phages PBSI, M2, SP 01, SP 10 and newly isolated B. natto phage NP-38 were examined for the induction of γ-polyglutamic acid (PGA) depolymerase synthesis. These phages, except M2, were capable of inducing the synthesis of the depolymerase in the infected bacteria. A direct evidence that the synthesis of depolymerase lay under the phage genome was obtained by the isolation of a depolymerase-deficient mutant of phage. A measurable amount of depolymerase was not detected in either intact or disrupted particles of phages. Thus, it seemed that the phage particles did not involve a bound enzyme.

The depolymerase was purified about 960 folds from the lysate of phage NP-38. The purified enzyme did not have a hydrolytic action on known protein substrate. The molecular weight was estimated to be about 20,000 from the result of a gel filtration.