The Activation of α-Chymotrypsinogen with Proteinase of Streptomyces griseus

Abstract

It was found that proteinase produced by Str. griseus can activate α-chymotrypsinogen. The enzyme which was activated by a limited proteolysis with Str. proteinase, in the pres-ence of β-phenylpropionate was homogeneous on column chromatography, centrifugal sedi-mentation pattern and paper electrophoresis. This enzyme is called σ-chymotrypsin. Sigma-chymotrypsin has almost the same enzymatic properties (specific activity, K_m, K_i) as these of π-chymotrypsin and is quite similar in the secondary and tertiary structure. N-terminal and C-terminal amino acids of o-chymotrypsin were examined and it was found N-terminal amino acid is isoleucine. Both lysine and arginine were found to be C-terminal amino acids. It was suggested that o-chymotrypsin is not homogeneous and the activation mechanism with Str. proteinase is somewhat different from that of tryptic activation. A schema of Str. proteinase activation is pro-posed and the activation mechanism is dis-cussed.