Role of a Sulfhydryl Group in the Structure and Function of Alkaline Proteases from a Thermophilic Actinomycete, Streptomyces rectus var. proteolyticus

Abstract

Thermophilic actinomycetes are generally defined as a group of actinomycetes which grow well above 50°C (1). It is well known that they are widely distributed in nature, inhabiting soils, composts, hay, peat, etc., and play an important role in the decomposition of organic matters.

In the past decade, a considerable attention has been paid to them as active producers of thermostable extracellular enzymes such as amylase, protease, cellulase, and cell wall lytic enzymes. As for proteolytic enzymes, most of them so far studied are alkaline proteases which are produced by several species belonging to the genera Streptomyces (2–4), Thermoactinomyces (5–14), Thermomonospora (10), and Micropolyspora (15, 16).