Occurrence of alpha 1-2-fucosylation in membrane glycoproteins of Morris hepatoma 7777 but not in liver. Aberrant type of fucosylation in a malignant tissue.
A comparative study was undertaken to characterize the linkages of L-fucose in N-glycans of plasma membrane glycoproteins from Morris hepatoma 7777, host liver and kidney cortex, as well as from rat serum. After in-vivo radiolabelling of rats with L-[6-3H]fucose, the asparagine-linked carbohydrate chains were released from delipidated plasma membrane glycoproteins, as well as from serum glycoproteins, by enzymic digestion with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase from Flavobacterium meningosepticum. They were then converted to their corresponding oligosaccharide alditols by reduction with sodium borohydride. Two specific alpha-L-fucosidases from almond emulsin and from Aspergillus niger, combined with affinity HPLC on immobilized Aleuria aurantia lectin were used to study the linkage of L-fucose in the oligosaccharide chains. Fucose alpha 1-2 linked to galactose, was present only in the plasma membrane of hepatoma 7777 (18% of total L-[3H]fucose in N-glycans), but was not expressed in host liver, kidney cortex and serum. None of the investigated sources contained an appreciable amount of fucose alpha 1-3/4 linked to N-acetyl-D-glucosamine. All the radioactively labelled oligosaccharides from host liver, kidney cortex and serum, but only 82% of these oligosaccharides from hepatoma, contained alpha-fucosyl residues linked at the C6 position of the proximal N-acetyl-D-glucosamine.
Nuck
R
R
Institut für Molekularbiologie und Biochemie, Freien Universität Berlin, Federal Republic of Germany.
Orthen
B
B
Reutter
W
W
D000818:Animals; D002240:Carbohydrate Sequence; D002462:Cell Membrane / Q000378:metabolism; D005643:Fucose / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry; D008969:Molecular Sequence Data; D051381:Rats; D013379:Substrate Specificity; D005644:alpha-L-Fucosidase / Q000378:metabolism
D008562:Membrane Glycoproteins; D005643:Fucose; D005644:alpha-L-Fucosidase