CHARACTERIZATION OF SUGAR CHAIN STRUCTURES OF HUMAN ALPHA-FETOPROTEINBY LECTIN AFFINITY ELECTROPHORESIS

alpha-Fetoprotein (AFP) glycoforms, defined as AFP with different chem ical structures of carbohydrate, were analyzed by affinity electrophor esis with several lectins of known specificities against complex-type oligosaccharides. Serum AFP samples from cord blood on full-term deliv ery and from patients with hepatocellular carcinoma and extrahepatic m alignancies including gastrointestinal tumors and yolk sac tumors were used. Two-dimensional lectin affinity electrophoresis and also lectin affinity chromatography coupled with lectin affinity electrophoresis were employed. More than ten AFP glycoforms were identified or charact erized using the above-mentioned AFP samples. Known specificities of t he lectins against complex-type oligosaccharides were refined or their additional specificities were found in this study. Lectin appeared to have specificity against carbohydrates by recognizing not only specif ic residues but also the whole carbohydrate molecule containing the re sidues, resulting in differential affinities for the lectin.