Synthesis and biological activity of a ketomethylene analogue of a tripeptide inhibitor of angiotensin converting enzyme

J Med Chem. 1980 Dec;23(12):1392-8. doi: 10.1021/jm00186a020.


An analogue of a tripeptide inhibitor of angiotensin converting enzyme, Bz-Phe-Gly-Pro, has been synthesized in which the amide bond connecting phenylalanine and glycine has been replaced by a ketomethylene group. This nonpeptide analogue, 20, shows more potent converting enzyme inhibiting activity, I50 = 0.07 microM, than Bz-Phe-Gly-Pro, I50 = 9.4 microM, or than the orally active D-3-mercapto-2-methylpropanoyl-L-proline (captopril, 1), I50 = 0.30 microM. Compound 20 has a Ki of 1.06 X 10(-7) and either competitive or noncompetitive enzyme kinetics depending on what substrate is used in the converting enzyme assay. In tests for inhibition of angiotensin I induced contractions in the guinea pig ileum, 20 has one-tenth the activity of 1.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Angiotensin I / antagonists & inhibitors
  • Angiotensin-Converting Enzyme Inhibitors*
  • Animals
  • Chemical Phenomena
  • Chemistry
  • Dipeptides / chemical synthesis*
  • Dipeptides / pharmacology
  • Guinea Pigs
  • In Vitro Techniques
  • Kinetics
  • Male
  • Muscle Contraction / drug effects


  • Angiotensin-Converting Enzyme Inhibitors
  • Dipeptides
  • compound 20
  • Angiotensin I