Abstract
1. Hydrolysis of benzoyl-Arg-NH2 and the activity of trypsinogen-activa-tion by the trypsinogen-kinase and other various proteases were examined. Both the trypsinogen-kinase (acid-protease from Asp. oryzae) and the acid-protease from Asp. saitoi could not hydrolyse benzoyl-Arg-NH2 but activated trypsinogen strongly.
2. The neutral-protease from Asp. oryzae has also a weak activity in trypsinogen-activation.
3. The preparation of the author's acid-protease has the activities of carboxypeptidase A, B, proteinase, and of hydrolysing L-Leu-L-Arg and L-Phe-L-Arg.
4. The relation between the substrate specificity of the acid-protease from Asp. oryzae and the mechanism of trypsinogen-activation by this enzyme are discussed.
The author wishes to express his thanks to Prof. Akabori of Osaka University for his kind guidance, and to Mr. Nomoto, Mr. Miura and Dr. Yoshida for supplying the used proteases, and to the staff of the Ando Laboratory of Tokyo University for giving the arginine containing peptides.
