The enzymes isolated from two selected cultures of thermophilic actinomycetesThermomonospora
fusca (A 29) and Thermoactinomyces vulgaris (A 60)-possess
proteolytic activity. The enzymes were purified more than 35- to 40-fold and showed
three bands each upon cellulose acetate electrophoresis at several pH values. Based
upon Sephadex gel filtration, molecular weights of 21,500 and 23,800 were calculated
for the active peaks of the enyzmes. The purified enzymes lysed heat-killed
cells of gram-positive and gram-negative bacteria, mycobacteria, and fungi and also
hydrolyzed casein. The enzymes were most active between a temperature range of
60 and 70 C and pH 8.0 and 9.0, and were significantly inhibited by potassium
permanganate, potassium ferricyanide, and iodine.