Abstract
Among three alkaline protease inhibitors (API-2a, -2b, -2c) produced by Streptomyces griseoincarnatus strain No. KTo-250, API-2b was converted to API-2c in the growing system.
The cultural conditions were examined exclusively for the production of API-2b→API-2c converting protease in the culture filtrate. The protease was purified about 1080-folds by salting-out with ammonium sulfate, column chromatography on DEAE-cellulose and gel filtration on Sephadex G-100.
The optimal and maximal caseinolytic activities of the protease were around pH 9.0 and at 28°C, respectively. The protease activity was inhibited by EDTA and DFP, but not by PCMB, o-phenanthroline, TPCK, TLCK, AP-I and S-SI. The protease was a DFP and EDTA-sensitive alkaline protease, and it required Ca2+ ion for its activity and stability.
