DEPENDENCE OF INTRACELLULAR PROTEOLYTIC-ENZYMES IN GROWING AND SPORULATING CELLS OF BACILLUS-MEGATERIUM ON CA2+ CONCENTRATION

Intracellular proteolytic activities of growing and sporulating cells of Bacillus megaterium were compared after their separation by size-ex clusion high-performance liquid chromatography. In both types of cells four soluble proteolytic activities, PI, PII, PIII and E, were found with M of more than 300, about 62, 36, and 20 kDa, respectively. PI wa s probably a complex of enzyme(s) or an enzyme associated with some st ructure. It was activated by Ca2+ but not by Mg2+ and stabilized by bo th divalent cations. PII, a major proteinase in both types of cells, w as a serine enzyme with the same Ca2+ and Mg2+ dependence as PI. PIII was a divalent-cation-independent enzyme with a very low activity. E c orresponded to the extracellular metalloenzyme produced by this organi sm. Possible regulation of proteolytic activity and protein degradatio n in vivo by Ca2+ during sporulation is discussed.