Abstract
Angiotensin I converting enzyme was purified from rabbit plasma by means of ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-200 gel filtration. The purified material was separated from angiotensinase, carboxypeptidase and L-leucyl-β-naphthylamidase, but could not be separated from di- or tri-peptidases. The specific activity of the enzyme was elevated 63 fold by the purification method. The purified material produced angiotensin II, His-Leu, histidine and leucine when incubated with angiotensin I at 37°C, pH 7.2 for 20 hours. This fact suggests that the enzyme hydrolyses the Phe-His bond of angiotensin I. The enzyme activity was inhibited by the addition of 10-3M EDTA. Optimum pH of the enzyme was about pH 7.2.
