Dual role of S-nitrosocaptopril as an inhibitor of angiotensin-converting enzyme and a nitroso group carrier.

The S-nitroso derivatives of captopril can act as an inhibitor of an angiotensin-converting enzyme in the presence of thiol such as glutathione. S-Nitrosocaptopril also rapidly transfers its nitroso moiety to a heme protein, which is presumably the responsible mechanism for the activation of guanylate cyclase. These results suggest that S-nitrosocaptopril may serve as an effective hypotensive agent.