Lectin-affinity chromatography of serum gamma-glutamyltransferase in liver disease

The variation of the carbohydrate chain of gamma-glutamyltransferase was studied in 45 liver patients by means of lectin affinity chromatography. Five lectins were used: concanavalin A, Ricinus communis I and II, Maclura pomifera and Ulex europaeus agglutinin. The binding towards Con A was shown to be independent from the binding towards the other lectins. Parallel variations of binding results against the galactose- and fucose-recognizing lectins were obtained. In liver steatosis, the binding results were comparable to those obtained in normal patients. Cirrhosis and metastasis patients showed a decreased binding towards Con A, while the binding against the various galactose- and fucose-recognizing lectins was increased. After neuraminidase treatment, an increased affinity towards all lectins was observed. However, differences in RCA I and RCA II binding between patients and controls still persisted. Besides sialic acid, also galactose and fucose residues contribute to serum gamma-glutamyltransferase heterogeneity.