The primary structure of the asialo-carbohydrate units of the first glycosylation site of human plasma alpha 1-acid glycoprotein.

The elucidation of the structures of the carbohydrate units linked to glycosylation site I of human plasma alpha 1-acid glycoprotein is described. These carbohydrate units can be grouped into compounds with bi- (class A) and triantennary (class B) structures and the triantennary structure with a fucose residue (class BF) (Fig. 1). The structural variability of the carbohydrate units of glycosylation site I and also of glycosylation sites II to V (Fournet, B., Montreuil, J., Strecker, G., Dorland, L., Haverkamp, J., Vliegenthart, J.F.G., Binette, J.P. and Schmid, K. (1978) Biochemistry 17, 5206--5214) accounts largely for the microheterogeneity of alpha 1-acid glycoprotein.