Specificity of the Amidase and Kininogenase Methode for the Determination of Rat Urinary Kallikrein

Summary: The specificity of the amidase and kininogenase methods for determining rat urinary kallikrein was studied. Male and female rat urine was employed. Esterase AI, A2 and kallikrein were separated by DEAE-Sephadex A-50 chromatography. Esterase AI showed no amidase activity towards the Substrate H-£>-Val-Leu-Arg-/?-nitroanilide. In contrast, esterase A2 and kallikrein attacked the Substrate, and the activity of kallikrein was especially inhibited by aprotinin, while esterase A2 was more sensitive to soybean trypsin inhibitor. Esterase AI did not show kininogenase activity, whereas esterase A2 showed this activity, but only towards the dog plasma Substrate. Kallikrein possessed kininogenase activity towards both dog and rat plasma kininogen. We believe that the most specific method for measuring rat urinary kallikrein activity is the kininogenase method using partially purified rat plasma kininogen