Brain renin from bovine anterior pituitary. Isolation and properties.

Brain renin has been purified 1,670,000-fold to homogeneity from bovine anterior pituitary in seven steps, including affinity chromatography on pepstatin-aminohexyl-agarose. The molecular weight of this enzyme is 36,000 as determined by gel filtration on Ultrogel AcA 44 and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has an isoelectric point of 5.25 and works best at physiological pH. In contrast to renal renin, bovine brain renin fails to bind to concanavalin A and four other lectins. The angiotensin I-forming activity of the purified brain renin was completely neutralized by anti-hog renal renin antibody. Rabbit antisera against pure brain renin showed a low degree of species and tissue specificity, reacting readily with hog brain renin and bovine and hog kidney renins. These results provide definite evidence for the presence of a functional brain renin-angiotensin system.