PURIFICATION AND PROPERTIES OF ENDOPEPTIDASE FROM RABBIT RED CELLS AND ITS PROCESS OF DEGRADATION OF ANGIOTENSIN

Endopeptidase, showing angiotensinase activity in rabbit red cells, was purified by fractionation with (NH4)2SO4, DEAE-cellulose column chromatography and Sephadex G-200 gel filtration. The specific activity of angiotensinase on the purified preparation was increased about 8000-fold compared with that of the crude hemolysate. The peptide bonds cleaved by the enzyme preparation in [α-l-Asp1, Ile5]-angiotensin II were Arg-Val, Tyr-Ile and Ile-His. It was demonstrated that hydrolysis of the Tyr-Ile bond with the enzyme was the first step in the inactivation process of angiotensin. The results indicated that the purified so-called angiotensinase might be an endopeptidase without hydrolytic activity on casein, p-toluenesulfonyl-l-arginine methyl ester and acetyl-l-tyrosine ethyl ester. © 1969.