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Identification of α‐fetoprotein‐P4 sugar chain as α 2→6 monosialylated biantennary complex‐type oligosaccharides with an exposed galactose on the mannose α 1→6 arm by two‐dimensional extended agarose gel‐lectin affinity electrophoresis
Author(s) -
Taketa Kazuhisa,
Fujii Yasuto,
Aoi Toshie,
Taga Hiroko,
Nishi Shinzo
Publication year - 1993
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.11501401125
Subject(s) - affinity electrophoresis , lectin , chemistry , agarose , affinity chromatography , biochemistry , oligosaccharide , alpha fetoprotein , galactose , microbiology and biotechnology , mannose , biology , hepatocellular carcinoma , enzyme , cancer research
Erythroagglutinating phytohemagglutinin (E‐PHA)‐reactive α‐fetoprotein (AFP)‐P4 and E‐PHA weakly‐reactive AFP‐P3 of sera from cord blood at term and from patients with hepatocellular carcinomas showed a mobility of monosialo‐AFP in two‐dimensional extended agarose gel‐E‐PHA affinity electrophoresis. Asialo‐AFP had as high an affinity for E‐PHA as that of monosialo‐AFP‐P4, while disialo‐AFP, AFP‐P2, revealed a negligible affinity for E‐PHA. For Allomyrina dichotoma lectin (allo A), asialo‐AFP had no affinity with a mobility of AFP‐A1s, monosialo‐AFP‐P4 had the highest affinity with a mobility of AFP‐A3, and monosialo‐AFP‐P3 had an intermediate affinity with a mobility of AFP‐A2s. The affinity of AFP‐P4 for E‐PHA was reduced by galactosidase digestion, indicating the presence of galactose residues, one sialylated and the other exposed. From the known high affinity of E‐PHA for biantennary complex‐type oligosaccharides with a terminal β 1→4 galactose of the Man α 1→6 antenna and from that of allo A for an α 2→6 sialylated β 1→4 galactose of the Man α1→3 antenna, together with the nonbisected biantennary structure of AFP‐P4 as deduced from its high affinity for concanavalin A, the sugar chain structure of AFP‐P4, which increases frequently in hepatocellular carcinomas, was identified as α 2→6 monosialylated nonbisected biantennary complex‐type oligosaccharides with an exposed β 1→4 galactose of the Man α 1→6 arm and with or without fucosylated core N ‐acetylglucosamine, and AFP‐P3 as similar oligosaccharides with an exposed β 1→4 galactose of the Man α 2→3 arm.