Regulation of the formation of proteinases inBacillus megaterium

Absrract The exocellular proteinases from the asporogenic and sporogenic strain ofBacillus megaterium KM were purified and characterized. They are both neutral metalloenzymes, having an optimum pH of 7.2. The bivalent metal cations, particularly calcium or magnesium, are essential for their activity. The curve of the relationship between the reaction velocity and the concentrations of Ca²⁺ resembles the Michaelis curve for substrate concentration. The enzymes also require metal cations for their stability. Both proteinases are inactivated byo-phenanthroline (lmm) and are resistant against diisopropyl fluorophosphate (lmm) and sodium-p-chloromercuribenzoate (lmm) treatment. In spite of the difference in biochemical regulation of their synthesis, these exocellular proteinases seem to be similar. The terms, megaterioproteinase A and megaterioproteinase S have been proposed for these enzymes.