Purification and Characterization of Alkaline Serine Protease from an Alkalophilic Streptomyces sp

Abstract

SAP, an extracellular alkaline serine protease produced by Streptomyces sp. YSA-130, was purified to homogeneity by CM-Sephadex column chromatography and crystallization. The enzyme was a monomeric protein with a molecular weight of 19, 000 as estimated by SDS-PAGE and gel filtration. The amino acid composition and amino-terminal sequence of SAP were similar to those of other bacterial serine proteases, i. e., Streptomyces griseus proteases A and B, Lysobacter enzymogenes α-lytic protease and Nocardiopsis dassonvillei subsp. prasina OPC-210 alkaline serine protease NDP-I. The optimum temperature and pH for the enzyme activity were 60°C and l1. 5. The enzyme was stable up 50°C, and between pHs 4 and 12. The activity was inhibited by Ag⁺, Hg²⁺, Co² +, sodium dodecyl sulfate, N-bromosuccinimide, diisopropyl phosphorofluoridate (DFP), 2, 3-butanedione, 5, 5'-dithiobis-(2-nitrobenzoic acid) (DTNB), iodoacetate, Nethylmaleimide (NEM), phenylmethanesulfonyl fluoride (PMSF), and phenylglyoxal.