Specific membrane-binding of angiotensin II--the role of degradative enzymes

The possible role of degradative enzymes was examined in the specific binding of angiotensin II (AII) to cell membranes. Red blood cell membranes did not bind AII specifically under any of the ambient conditions studied, indicating a lack of AII receptors and no role for the degradative enzymes in specific binding. Rabbit aorta smooth muscle cell membranes bound AII specifically, and this binding had similar characteristics to those previously described for this preparation. It is concluded that specific binding of AII to cell membranes does not involve degradative enzymes, and probably represents binding to the biologically active receptor.