No abstract

1 "Reversible inactive" trypsin was the designation of Kunitz and Northrop (1934) for the form of trypsin obtained by raising the temperature or by making the solution strongly alkaline. This form was in equilibrium with active trypsin (Ta;=± Ti) but if allowed to stand, unless at very low pH (2), trypsin soon irreversibly lost its activity (irreversible inactive). Evidently, if considerably ionized by either acid or base, 2766 BIOCHEMISTRY, VOL.

Vibrio vulnificus (lactose-positive vibrio) produced collagenase when grown in 2% synthetic sea salts supplemented with hydrolyzed casein. The addition of collagen or peptone to the medium increased the level of collagenase production. Collagenase activity was inhibited by EDTA but not by fetal calf serum.

Merkel, Joseph R. (Fort Johnson Marine Biological Laboratory, College of Charleston, Charleston, S.C.), Eugene D. Traganza, Barid B. Mukherjee, Travis B. Griffin, and J. M. Prescott . Proteolytic activity and general characteristics of a marine bacterium, Aeromonas proteolytica sp. n. J. Bacteriol. 87: 1227–1233. 1964.—A highly proteolytic bacterial species was isolated from the alimentary canal of the marine borer, Limnoria . The morphological and biochemical characteristics of the organism indicated that it was a new Aeromonas species, for which the name A. proteolytica is proposed. When freshly isolated, the organism required seawater for growth; but, upon prolonged culture in the laboratory, it was able to grow in media of greatly reduced salt concentration, provided that relatively large amounts of peptone were supplied. Peptone or hydrolysates of casein were capable of supplying all organic nutrients required for growth and proteinase production. Certain individual amino acids were also able to furnish all energy, carbon, and nitrogen requirements. Inorganic nitrogen was utilized in the presence of citrate, but could not serve as the only source of nitrogen in the presence of glucose. The organism was facultatively anaerobic, but best growth and proteinase production occurred only with vigorous aeration. The amount of growth obtained in 24 hr increased rapidly as the incubation temperature was increased up to a maximum of 40 C, but no growth occurred at 42 C.