High prevalence of 2-mono- and 2,6-di-substituted Manol-terminating sequences among O-glycans released from brain glycopeptides by reductive alkalinehydrolysis
Wg. Chai et al., High prevalence of 2-mono- and 2,6-di-substituted Manol-terminating sequences among O-glycans released from brain glycopeptides by reductive alkalinehydrolysis, EUR J BIOCH, 263(3), 1999, pp. 879-888
Di- to heptasaccharides isolated from total nondialyzable brain glycopeptid
es after release by alkaline borohydride treatment have been subjected to m
ass spectrometric and nuclear magnetic resonance spectroscopic analyses sup
plemented by TLC-MS analyses of derived neoglycolipids. A family of Manol-t
erminating oligosaccharides has been revealed which includes novel sequence
s with a 2,6-disubstituted Manol:
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In contrast to the Manol-terminating HNK-1 antigen-positive chains describe
d previously that occur as a minor population [Yuen, C.-T, Chai, W., Lovele
ss, R.W., Lawson, A.M., Margolis, R.U. & Feizi, T. (1997) J. Biol. Chern. 2
72, 8924-8931], the above oligosaccharides are abundant. The ratio of these
compounds to the classical N-acetylgalactosaminitol-terminating oligosacch
arides is about 1:3. Thus, there appears to be in higher eukaryotes a major
alternative pathway related to the yeast-type protein O-mannosylation, the
enzymatic basis and functional importance of which now require investigati
on.