Human plasma angiotensinogen: a review of purification procedures.

The current status of the purification and characterization of human angiotensinogen is reviewed. One problem encountered in the past has been the copurification of a protein with similar porperties. This protein has tentatively been designated alanine-protein. An efficient separation of angiotensinogen and alanine-protein was obtained on a zinc chelate column. Alanine-protein has been purified and its amino acid and carbohydrate composition determined. The COOH-terminal amino acid and the NH2-terminal amino acid were determined to be serine and alanine, respectively. Alanine-protein exhibited multiple forms on isoelectric focusing.