Abstract
The plasma and kidney angiotensinases were compared in the rat. Effects of acid and alkali treatments and of enzyme inhibitors on the angiotensinase activities and the renin-angiotensionogen reaction were studied. Angiotensinase activity of the plasma was greatest near neutral pH at 37°C and was blocked almost completely by dialysis against disodium ethylenediaminetetraacetic acid (EDTA). The kidney angiotensinase at neutral pH was also inactivated by acidification and dialysis against EDTA. The activity having a optimum pH of 4.5 to 5.0 was not affected by the dialysis but was inhibited by alkali or diisopropyl fluorophosphate. The renin-angiotensinogen reaction was least affected by incubation of the acid-treated and dialysed kidney extract with the dialysed plasma at pH 7.4 and 37°C.
