EXPRESSION OF THERMOSTABLE ALKALINE PROTEASE GENE FROM THERMOACTINOMYCES SP. E79 IN ESCHERICHIA-COLI AND HEAT ACTIVATION OF THE GENE-PRODUCT

The expression of Thermoactinomyces sp. E79 protease gene cloned into E. coli was highly host-dependent and the levels of protease expressio n was most stable in E. coli RR1 and E. coli HB101. Heating the intrac ellular extract at 70 degrees C for 15 min converted the inactive reco mbinant E79 protease to its active mature form and also resulted in pu rification of the enzyme in a single step. Addition of 10 mM CaCl2 to the E79 protease decreased its autolysis and increased its thermal sta bility.