Tripeptidyl carboxypeptidase activity of kininase II (angiotensin-converting enzyme).
The degradation of des-Arg9-brady kinin and its analogues by highly purified preparations of hog lung and kidney kininase II (angiotensin-converting enzyme; peptidyldipeptide hydrolase, EC 3.4.15.1) was studied. The degradative peptides fragments were separated and isolated by high performance liquid chromatography and identified by amino acid analysis. Both enzymes released C-terminal tripeptides from des-Arg9-bradykinin, des-Arg9-(Leu8)-bradykinin, Pro-Pro-Gly-Phe-Ser-Pro-Phe, Pro-Gly-Phe-Ser-Pro-Phe, Gly-Phe-Ser-Pro-Phe, Bz-Gly-Ser-pro-Phe and Bz-Gly-Ala-Pro-Phe. Hydrolysis of Phe-Ser-Pro-Phe, Bz-Gly-His-Pro-Phe, Bz-Gly-Phe-Pro-Phe and Bz-Gly-Gly-Pro-Phe by both enzymes was negligible. These data indicate that kininase II can release C-terminal tripeptides of substrates having a proline residue in the penultimate position such as des-Arg9-bradykinin and its analogues, and that this enzyme is able not only to act as a dipeptidyl carboxypeptidase but also acts as a tripeptidyl carboxy-peptidase. The tripeptidyl carboxypeptidase enzyme was sensitive to inhibition by kininase II inhibitors.
D000818:Animals; D002712:Chlorides / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008168:Lung / Q000201:enzymology; D009842:Oligopeptides / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
D002712:Chlorides; D009842:Oligopeptides; D007703:Peptidyl-Dipeptidase A