The coexistence of Ser84 in renin and His13 in angiotensinogen brings a pH profile of two separate peaks to the reaction of human renin and sheep angiotensinogen.

The pH dependence and kinetics parameters of renin-angiotensinogen reactions were determined using wild-type and S84G mutant human renins and wild-type and H13Y mutant sheep angiotensinogens. It is explained in this report that (i) renin catalyzes acidic and basic reactions of which the optimum pHs are 5.5 and 7.