A subfraction of human fibrinogen with high sialic acid content and elongated gamma chains.

Fibrinogen isolated from normal human single donor or pool plasma was fractionated by DEAE-cellulose chromatography. Three different fibrinogen subfractions were obtained. The most acidic fraction comprising 22% of the whole fibrinogen pool was prominent by two special features: 1) its sialic acid content was significantly higher than that of bulk fibrinogen, namely 8 mol of sialic acid/mol of fibrinogen versus 6 mol in bulk fibrinogen. 2) Two-dimensional electrophoresis of the polypeptide chains obtained after reduction revealed a preferential accumulation in this subfraction of the elongated gamma chains previously described as gamma chain heterogeneity of whole human fibrinogen.