Lipid linked oligosaccharide biosynthesis

Fig. 45.—Pathway of the Biosynthesis of Lipid-linked Oligosaccharide Precursor of the N-Acetyl-lactosaminic Type of Glycans, and of the Intermediary Glycopeptide. (See general reviews 126-136, 226, and 227.)...

Structures of dolichol phosphate, GlcNAc-P-P-Dol, and Man-P-Dol. GlcNAc-P-P-Dol is the first compound formed in the biosynthesis of the lipid-linked oligosaccharide shown in Figure 16-5. Replacement of GlcNAc by -OH in GIcNAc-P-P-Dol yields dolichol diphosphate (dolichol pyrophosphate). Replacement of Man by Glc in Man-P-Dol yields Glc-P-Dol. 

Figure 16.17 Biosynthesis of the lipid-linked oligosaccharide intermediate. 

Membrane preparations from immature stages of the fruit fly Ceratitis capitata catalyse the transfer of o-mannose into lipid-linked oligosaccharides. The lipid-linked trisaccharide has been partially characterized and tentatively assigned the structure D-mannosyl -> NN diacetylchitobiosyl-poly(prenyl-pyrophosphate). These insect poly(prenyl)-oligosaccharides may participate in glycoprotein biosynthesis. 

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