Effect of thrombin on the molecular weights of N-terminal fragments of human fibrinogen

Abstract Cyanogen bromide cleaves the human fibrinogen molecule to produce several fragments, one of which consists of amino terminal components of each of the three chains, α(“A”), β(B) and γ, which comprise the “N-terminal disulfide knot of fibrinogen”. Sedimentation equilibrium experiments indicate that it is a dimer which can be dissociated into monomeric chain components by reduction and alkylation of cystine residues. It has further been proven that the N-terminal disulfide knot and its α(“A”) and β(B) monomeric units as well retain their susceptibility to thrombin cleavage.