Structural study of the O-linked sugar chains of human leukocyte tyrosine phosphatase CD45.
The O-linked sugar chains of the human leukocyte cell surface glycoprotein CD45 were released as tritium-labeled oligosaccharides by beta-elimination in the presence of NaB3H4. Mono Q column chromatography revealed that they comprise neutral (64%) and acidic (36%) oligosaccharides, the latter of which were converted to neutral ones by Arthrobacter ureafaciens sialidase treatment. Structural studies of each oligosaccharide fractionated on a Bio-Gel P-4 column by sequential exoglycosidase digestion and by methylation analysis revealed that human leukocyte CD45 contains mainly core 1 and core 2 oligosaccharides, 15% of which are modified with poly (N-acetyllactosamine) chains in different extensions. CD45 consists of several isoforms which were isolated after cell surface sialic acid residues were labeled by periodate/NaB3H4 treatment. Bio-Gel P-6 column chromatography of a mixture of the tritium-labeled glycopeptide/oligosaccharides obtained by pronase-digestion followed by mild alkaline borohydride treatment showed that distribution of the sialylated core 2 oligosaccharides is different among CD45 isoforms.
Furukawa
K
K
Department of Biosignal Research, Tokyo Metropolitan Institute of Gerontology, Japan. furukawa@tmig.or.jp
Funakoshi
Y
Y
Autero
M
M
Horejsi
V
V
Kobata
A
A
Gahmberg
C G
CG
D002240:Carbohydrate Sequence; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D017493:Leukocyte Common Antigens / Q000737:chemistry*; D007962:Leukocytes / Q000737:chemistry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*
D009844:Oligosaccharides; D017493:Leukocyte Common Antigens