Abstract
Two phosphoryl derivatives, phosphoryl-alanyl-proline (P-AP) and dibenzylphosphoryl-alanyl-proline (DBP-AP) were synthesized and the inhibitory activities of converting enzyme of these derivatives were evaluated and were compared with captopril by assessing the percent inhibition of the pressor responses to angiotensin I (300 ng/kg i.v.) following intravenus administration of these derivatives and captopril in bilaterally nephrectomized and urethane anesthetized rats. P-AP was shown to be a potent converting enzyme inhibitor, about one tenth as potent as captopril in weight basis while its duration of action was the shortest of them all. DBP-AP had the slowest onset of the action and the duration of the action was much longer than captopril suggesting that this derivative exerts its inhibitory action after being metabolized into yet unidentified form.
