Thermostable Proteinases from a Luminous Bacterium, Vibrio logei Strain CPM-D3. Purification and Some Properties

Two proteinases (I and II) from an intestinal luminous bacterium, Vivrio logei strain CPM-D3, were purified. The molecular weights of the proteinases I and II were estimated to be 62000 and 54000, respectively. These enzymes were most active at pH 9.0 and 60°C (proteinase I) and 50°C (proteinase II), respectively. These enzyme activities were inhibited by orthophenanthroline, but not by ethylenediamine-tetraacetic acid and phosphoramidon. Metal ions such as Cu2+, Hg2+ and Ni also inhibited these enzyme activities. Both enzyme activities were not affected by heat treatment at 100°C for 30min.