Activation of Kidney Prorenin by Kidney Cathepsin B Isozymes1

Abstract
Kidney prorenin was converted to a form of active renin by kidney cathepsin B isozymes. The three isozymes showed similar catalytic behavior for prorenin. The optimal pH for the activation was in the range of 4.0–5.0 and the reaction was completely inhibited by leupeptin. The molecular weight and the isoelectric point of the activated prorenin were 40,000 and pH 4.9. As a minor product, an activated prorenin having an isoelectric point of 5.2 was also produced.