Rat liver kininase, a serine peptidase

A serine peptidase (RLK1) was partially purified from rat liver homogenates. Its molecular weight was 80,000, and its optimum pH was 7.5. Bz-Tyr-O-Et was hydrolyzed by the enzyme, which was inhibited by Ip2PF, PMSF and by Tos-Phe-CH2Cl. The bonds cleaved by the enzyme were Phe5-Ser6 and Phe8-Arg9, when bradykinin was used as substrate.