DISTRIBUTION OF CARBOHYDRATE AMONG POLYPEPTIDE CHAINS AND PLASMIN DIGEST PRODUCTS OF HUMAN FIBRINOGEN

Human fibrinogen was subjected to sulfitolysis and the constituent polypeptide chains were isolated. Each of the three chain types contained glucosamine and hexose (analyses for sialic acid were not performed). The glucosamine and hexose contents of fibrinogen were satisfied by the sum of the corresponding values for a pair of each of the three chains. Pronase digest glycopeptides from the three chains were compared with those from three fractions of a prolonged plasmin digest of fibrinogen (designated fractions D, E, and F). Fraction D of about 50,000 mol wt yielded a glycopeptide fraction which was similar to that from the α(A)-chain. Fraction E of about 30,000 mol wt contained the glycopeptide portion of the γ-chain, while the glycopeptide portion of the β (B)-chain was contained in a heterogeneous low molecular weight fraction, here designated F. The values for molecular weight, glycopeptide composition, and amino acid composition of fraction E resembled those for the disulfide knot" of fibrinogen which contains the N-terminal portions of the three chains. © 1969."