Studies on the Distribution of Proteolytic Enzymes in the Internal Organs of Octopus

Abstract

The distribution of proteolytic enzymes in the internal organs of octopus, Octopus vulgaris CUVIER. was investigated. 1. Proteolytic activities were detected in all the organs examined, though there were remarkable differences in the activities among the organs. 2. Proteolytic enzymes of such organs as liver, renal sac, heart, branchial heart and pancreas showed two optimum pH, near 2.5 and 6.0, for casein hydrolysis and the proteolytic activity of each organ was higher at pH 2.5 than at pH 6.0. The pancreatic enzyme scarcely hydrolyzed casein in the alkaline region. As for the activities of these organ enzymes, that of liver was the highest, followed by those of branchial heart, pancreas, renal sac, and heart in that order. 3. The anterior salivary gland and the submaxillary gland contained a proteolytic enzyme with optimum pH near 2.5. That of the former possessed the highest activity after the branchial heart enzyme. 4. The proteolytic activity of the posterior salivary gland was remarkably high in the alkaline region, which means that it possessed the highest activity of all the organs investigated. The pH optimum was near 8.5. 5. Proteolytic enzymes of digestive organs, such as crop, stomach, coecum and intestine, showed three optimum pH near 2.5, 6.0 and 7.5. They possessed only low activities, especially at alkaline pH. © 1972, The Japanese Society of Fisheries Science. All rights reserved.