サケ幽門垂カチオニックトリプシンの性質

抄録

Praperties of the cationic trypsin designated as PII-1 which was purified from the pyloric caeca of chum salmon Oncorhyncus keta were compared with the properties of bovine cationic trypsin (BCT) determined in the same conditions.
The optimum pH of the hydrolysis for p-tosyl-L-arginine methyl ester (TAME) was found to be 8.0, and of the caseinolytic activity was 10-10.5 for PII-1 and 7-10 for BCT. Both enzymes specifically hydrolyzed arginine and lysine methyl ester, they were activated with Ca²⁺, Mg²⁺ and Mn²⁺, and were stable at low pH, and readily inactivated by autolysis. Stability of PII-1 to the autolysis was increased in the presence of Mg²⁺, Ba²⁺ and Sr²⁺ as well as Ca²⁺ and Mn²⁺ which are a stabilizer of BCT. The termal stability of PII-1 was significantly lower than that of BCT.
These results show that PII-1 has similar properties to BCT more than anionic trypsins from the pyloric caeca of chum salmon.