| Abstract |
A soluble intracellular protease from cells of Pseudomonas carboxydovorans, a carboxydobacterium, grown on nutrient broth was purified 68-fold in five steps to better than 95% homogeneity with a yield of 2.4% using azocasein as a substrate. The enzyme activity was not detected from cells grown on pyruvate, succinate, acetate, or CO as a sole source of carbon and energy. The molecular weight of the native enzyme was determined to be 53,000. Sodium dodecyl sulfate-gel electrophoresis revealed the purified enzyme a monomer. The enzyme was found to be a serine-type protease. The enzyme activity was inhibited completely by several divalent cations such as Cd^2+, Cu^2+, Hg^2+, and Fe^sup 2+. The enzyme was also inhibited by EGTA, but was stimulated by iodoacetamide. The optimal pH and temperature for the enzyme reaction were found to be 8.0 and 50℃, respectively. The enzyme was inactive on CO dehydrogenase. |
