Angiotensin-converting enzyme from rabbit pulmonary particles.

Angiotensin-converting enzyme has been solubilized from rabbit pulmonary particles and purified to homogeneity. The molecular weight of the native enzyme was estimated to be about 136,000 by glycerol gradient centrifugation, and a value of 140,000 was obtained for the reduced denatured protein by disc-gel electrophoresis in the presence of sodium dodecyl sulfate and 2-mercaptoethanol. The enzyme was found to be a glycoprotein with carbohydrate accounting for approximately 16% of its dry weight. The major sugar residues were identified as galactose, N-acetylglucosamine, and mannose, with smaller amounts of fucose and sialic acid. The homogeneous enzyme catalyzed the release of His-Leu from the COOH-terminus of angiotensin I and of Phe-Arg and Ser-Pro from that of bradykinin.