Demonstration of glycosylation variants of human fibrinogen, using the new technique of glycoprotein lectin immunosorbent assay (GLIA).

A new highly sensitive method, incorporation the ELISA technique (enzyme-linked immunosorbent assay), is described for the quantitation of the glycan residues of glycoproteins. With the aid of this "glycoprotein-lectin immunosorbent assay (GLIA)", it is possible to determine the nature of the glycan residues of a single protein in a glycoprotein mixture, without prior purification. The GLIA can be used for the accurate determination of the inhibitor constant for the interaction of any monosaccharide with any lectin. Using the described technique, glycosylation of human fibrinogen from plasma and amniotic fluid were compared. In fibrinogen from amniotic fluid a "fetal" glycosylation type could be demonstrated. In addition, evidence is presented for the first time that plasma fibrinogen possesses (GlcNAc beta 1----4Man beta) residues (bisecting GlcNAc) and O-glycosidically bound carbohydrate units. Preliminary results were published as abstract (E. Köttgen et al. (1988) Fresenius Z. Anal. Chem. 330, 448).