CARBOHYDRATE-COMPOSITION OF SERUM TRANSFERRIN ISOFORMS FROM PATIENTS WITH HIGH ALCOHOL-CONSUMPTION

Normal human serum transferrin is present in several isoforms, due to differences in glycosylation. Transferrin has two potential glycosylat ion sites, both normally occupied by oligosaccharide chains. Two of th e transferrin isoforms, called carbohydrate deficient transferrin, are specifically increased in patients with high alcohol consumption. In this study, five isoforms of transferrin were isolated from patients w ith high alcohol consumption. N-linked glycans were released by N-glyc osidase digestion and were radioactively labeled by (NaBH4)-H-3 reduct ion. The purified oligosaccharides were analyzed by high-pH anion-exch ange chromatography, and the carbohydrate composition of each individu al transferrin isoform was determined. The carbohydrate deficient tran sferrin isoforms were found to lack one or both of their entire carboh ydrate chains. (C) 1995 Academic Press, Inc.