Hog renin substrate has been separated into three major (A, B, and C) and two minor forms (D and E) by DEAE cellulose chromatography. Two of the major forms (B and C) have been further fractionated into two additional types (1 and 2) by countercurrent distribution.
The purification of substrates A, C1, and C2 has been completed. Analysis shows that all three are glycoproteins with molecular weights of about 57,000, and have similar amino acid compositions. Differences exist in the sialic acid, glucosamine, and neutral hexose content, which may account for different physical properties.
All the forms of the substrates are attacked by renin at similar rates, and appear to yield the same angiotensin I.