Localization of kininogenase in the rat kidney

Abstract

1 . The rat kidney kininogenase (KGA) activity was located mainly in the kidney cortex. 2 . Differential centrifugation of kidney cortex homogenate revealed that the microsomal fraction contained more KGA activity per unit of protein than the other subcellular fractions. 3 . Subfractionation of the microsomal fraction showed that the KGA activity was recovered in a subfraction also containing high specific activity of both alkaline phosphate and glucose-6-phosphatase. It is suggested that the KGA activity is localized in the plasma membrane and/or endoplasmic reticulum membranes of kidney cortical cells. 4 . Hydrolysis of N-α-benzoyl-l-arginine ethyl ester at pH 8.5 paralleled the KGA activity.