Studies on pancreatic enzymes in fish. IX. Purification and some properties of two carboxypeptidases B from the catfish pancreas

°No carboxypeptidase A activity was detected in the extract of pancreas of the cafish Parasilurus asotus. However, when the extract was left at 4C, carboxypeptidase A activity increased with the time and reached to a maximum level after 4 days. These results indicate that carboxypeptidase A is stored as zymogen in the pancreas.Carboxypeptidase A was isolated from the autoactivated extract of the catfish pancreas by CM-cellulose column chromatography and affinity chromatography. The homogeneity of the enzyme was demonstrated by polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated as 34, 000 by SDS-polyacrylamide gel electrophoresis. The amino acid composition of the catfish enzyme was found to be similar to those of the carboxypeptidases A from other species.