Effect of temperature and chloride on steady-state inhibition of angiotensin I-converting enzyme by enalaprilat and ramiprilat.

The kinetics of the steady-state inhibition of angiotension I-converting enzyme (EC 3.4.15.1) at 25 degrees C and 37 degrees C with enalaprilat and ramiprilat can be simulated, assuming only one inhibitor-binding site, consistent with a 1:1 stoichiometry if the protein concentration was determined by amino acid analysis. In this temperature range the apparent inhibition constants for ramiprilat and enalaprilat were roughly doubled by a decrease in the chloride concentration from 0.300 M to 0.120 M.