Primary Structure of Human Fibrinogen and Fibrin

Abstract The cleavage of human fibrinogen in 70% formic acid with CNBr has been studied. A fragment containing the NH2-terminal portions of the three chains has been obtained from the reaction mixture. After reduction and alkylation the NH2-terminal fragments of the α(A) and α(AP) chains have been isolated in essentially pure form by gel filtration and chromatography. The amino acid sequence of these fragments has been determined. Evidence is presented for the occurrence in the α(A) and α(AP) chain preparations of the chain variants α(AY) and α(AYP). The relation between structure and function of fibrinogen is discussed.