text: This vast scope of functionality for a single protein makes it the ideal model for research regarding other zinc proteases of unknown structure.  Recent biomedical research on collagenase, enkephalinase, and angiotensin-converting enzyme used carboxypeptidase A for inhibitor synthesis and kinetic testing.  For example, a drug that treats high blood pressure, Captopril, was designed based on a carboxypeptidase A inhibitor.  Carboxypeptidase A and the target enzyme of Captopril, angiotensin-converting enzyme, have very similar structures, as they both contain a zinc ion within the active site.  This allowed for a potent carboxypeptidase A inhibitor to be used to inhibit the enzyme and, thus, lower blood pressure through the renin-angiotensin-aldosterone system.