Dithiothreitol Augments Renin Activity by an Action on Renin Substrate 1

Abstract

Summary

Dithiothreitol (DTT) increases the generation of angiotensin when bovine renin acts on bovine substrate or hog substrate. Kinetic analysis indicates that the V_max increases without a change in K_m. Pretreatment of bovine renin with DTT followed by dilution of the DTT to a low concentration does not augment renin activity, while pretreatment of the substrate and a similar dilution reveals marked potentiation. N-Ethylmaleimide (NEM) does not inhibit renin activity but does prevent the augmenting effect of DTT present during the incubation. It is concluded that DTT augments renin activity by an action on renin substrate and that renin does not fall in the category of sulfhydryl-dependent enzymes.

We acknowledge the valuable technical assistance of Mr. Paul Arnold and Mrs. Roselle Poisner.