[Isolation and purification of angiotensinogen from swine and sheep plasma]

Angiotensinogen (a substrate of renin) was isolated from pig and sheep blood plasma. Content of angiotensinogen was estimated in the preparations obtained by an indirect biological method, which was based on estimation of an increase in blood pressure in rats, caused by angiotensin, liberated from angiotensinogen during incubation with renin. The preparation, obtained by ammonium sulphate fractionation of pig blood plasma, contained 0.4% of angiotensinogen. Angiotensinogen was also isolated from sheep blood plasma using ammonium sulphate fractionation, DEAE-Sephadex chromatography and gel filtration through Sephadex G-100; this preparation contained 10-13% of angiotensinogen.