Some Characteristics of Proteolytic System of a Marine Bacterial Species.

Abstract

Filtrates from a pure culture of a marine bacterial species contain an active proteolytic system which rapidly hydrolyzes denatured hemoglobin. Proteinase activity after 54 to 56 hours of growth is so high that culture filtrates must be diluted for accurate assays, even with short incubation periods. In the crude system studied, activity is proportional to time of incubation during the early part of the reaction, and is proportional to enzyme concentration over the 10-fold range tested. The system has optimal activity at pH 8, is activated by Co++ and Zn++ ions, and is inhibited by Fe+++, Hg++, and Cu++ ions. Disulfide linkages appear to be required for activity since reducing agents inhibit the enzyme, while p-chloromercuri-benzoate is without effect. The enzyme system is stable at 48[degree] C for incubation periods of 40 minutes, but temperatures above 50[degree] C reduce activity even at shorter incubation periods. Heating at 70[degree] C for 7.5 minutes before assay reduces activity to half maximum.