Characterization of bovine atrial angiotensin-converting enzyme

Bovine atrial angiotensin-converting enzyme (ACE) was purified to electrophoretic homogeneity. The purification procedure included ion-exchange chromatography on DEAE-Toyopearl 650M, affinity chromatography on lisinopril-agarose and eel filtration on Sephadex G-100. The bovine atrial ACE exhibited similar sensitivities to inhibition by lisinopril and captopril as lung AC E (the K,values for the atrial and lung enzymes differed insignificantly). However, the kinetic parameters of hydrolysis of some synthetic tripeptide substrates (FA-Phe-Gly-Gly, FA-Phe-Phe-Arg, Cbz-Phe-His-Leu, Hip-His-Leu) catalyzed by bovine atrial and lung ACE varied to a greater extent. The enzymes were also characterized by some differences in activation by chloride, nit rate, and sulfate an ions. These data support the hypothesis of tissue specificity of ACEs.