Proteolytic enzymes of the K-1 strain of Streptomyces griseus obtained from a commercial preparation (Pronase). Purification and characterization of the carboxypeptidase.

We described earlier the facilitated purifications of the trypsin and aminopeptidase components present in Pronase (Vosbeck, K. D., Chow, K. -F., and Awad, W. M., Jr. (1973) J. Biol. Chem. 248, 6029-6034). A partially resolved protein mixture left over after one of the steps in that procedure was passed through a Sephadex G-75 column. By this means, a component with carboxypeptidase activity was separated from associated serine endopeptidases. Further purification of this exopeptidase to apparent homogeneity was acheived by refiltration through the same Sephadex column and by CM-cellulose chromatography. A single protein band was observed after acrylamide gel electrophoresis; analysis by sedimentation equilibrium using the meniscus depletion method gave a molecular weight of 30,300. This enzyme demonstrates activity against Nalpha-benzyloxycarbonylglycyl-L-leucine and hippuryl-D,L-phenyllactate; no activity was found against Nalpha-acetyl-L-tyrosine ethyl ester, Nalpha-benzoyl-D,L-arginine-p-nitroanilide, or L-leuckne-p-nitroanilide. The maximum activity lies between pH values of 7 and 8; the enzyme is stable between pH values of 6 and 10. At room temperature 1,10-phenanthroline inactivates the enzyme completely whereas EDTA ha...Continue Reading