ARTICLE: PDF OnlyCumin Frédéric; Nisato, Dino; Gagnol, Jean-Pierre; Corvol, PierreJournal of Cardiovascular Pharmacology: 1987 - p 102-104 Free Abstract Summary The interaction between human renin and a potent pepstatin analog, SR 42128, has been investigated using binding studies. Binding and enzymatic assays were performed at pH 5.7 and pH 7.4. We found one specific inhibitor binding site per molecule of renin at both pH's. The dissociation constant (KD) obtained at equilibrium was 14-field lower at pH 5.7 than at pH 7.4, showing a pH effect on binding of [3H]SR 42128. A similar de-crease was measured in enzymatic studies. In nonequilibrium conditions, we demonstrated that only association kinetic constants have been affected by pH variations. Radioligands provided interesting tools to investigate enzyme-inhibitor relationships. Copyright © 1987 Wolters Kluwer Health, Inc. All rights reserved.