Potent radiolabeled human renin inhibitor, (/sup 3/H)SR42128: enzymatic, kinetic, and binding studies to renin and other aspartic proteases
The in vitro binding of (/sup 3/H)SR42128 (Iva-Phe-Nle-Sta-Ala-Sta-Arg), a potent inhibitor of human renin activity, to purified human renin and a number of other aspartic proteases was examined. SR42128 was found to be a competitive inhibitor of human renin, with a K/sub i/ of 0.35 nM at pH 5.7 and 2.0 nM at pH 7.4; it was thus more effective at pH 5.7 than at pH 7.4. Scatchard analysis of the interaction binding of (/sup 3/H)SR42128 to human renin indicated that binding was reversible and saturable at both pH 5.7 and pH 7.4. There was a single class of binding sites, and the K/sub D/ was 0.9 nM at pH 5.7 and 1 nM at pH 7.4. The association rate was 10 times more rapid at pH 5.7 than at pH 7.4, but there was no difference between the rates of dissociation of the enzyme-inhibitor complex at the two pHs. The effect of pH on the binding of (/sup 3/H)SR42128 to human renin, cathepsin D, pepsin, and gastricsin was also examined over the pH range 3-8. All the aspartic proteases had a high affinity for the inhibitor at low pH. However, at pH 7.4, (/sup 3/H)SR42128 was bound only to human renin and to none of the other aspartic proteases. Competitive binding studies with (/sup 3/H)SR42128 and a number of other inhibitors on human renin or cathepsin D were used to examine the relationships between structure and activity in these systems. The study as a whole indicates that pH plays a major role in the binding of (/sup 3/H)SR42128 to aspartic proteases and that the nature of the inhibitor residue reacting with the renin S/sub 2/ subsites is of critical importance for the specificity of the renin-inhibitor interaction.
- Research Organization:
- INSERM, Paris, France
- OSTI ID:
- 5303753
- Journal Information:
- Biochemistry; (United States), Vol. 26:24
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rational design of renin inhibitors: x-ray studies of aspartic proteinases complexed with transition-state analogues
Slow step after bond-breaking by porcine pepsin identified using solvent deuterium isotope effects
Related Subjects
ENZYME INHIBITORS
BIOCHEMICAL REACTION KINETICS
CONFIGURATION INTERACTION
RENIN
ENZYME ACTIVITY
IN VITRO
MAN
PH VALUE
TRITIUM COMPOUNDS
ANIMALS
ENZYMES
HYDROLASES
KINETICS
LABELLED COMPOUNDS
MAMMALS
NONSPECIFIC PEPTIDASES
PEPTIDE HYDROLASES
PRIMATES
REACTION KINETICS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques