Complement Associated Peptidase Activity of Guinea Pig Serum

[摘要] Previous workers have demonstrated that hemolytic complement can be inhibited by peptides containing an aromatic amino acid and that C′3 is, in all likelihood, the inhibited component of complement. In the present study, EAC′1a,4,2a,3 have been shown to enzymatically hydrolyze glycyl-l-tyrosine as shown by the kinetics, pH optimum and dependence on concentration of cells and substrate. This peptidase activity is related to complement, and specifically to the presence of C′3 on the cells. However, EAC′1a,4,2a,3 cells prepared with partially purified C′3 have not been sactive enzymatically, with two significant exceptions. In these instances the C′3 was prepared by a variant of the standard procedure, and clear-cut implication of C′3 as the enzyme was obtained. Certain other data in this work indicate that the hydrolytic reaction is complex and point to a possible need for cofactor or enhancing substance for enzymatic activity. The search for such a factor is presented in the subsequent study.

[学科分类] 生物科学（综合）