Effect of mannosamine on the formation of lipid-linked oligosaccharides and glycoproteins in canine kidney cells
Madin-Darby canine kidney (MDCK) cells normally form lipid-linked oligosaccharides having mostly the Glc3Man9GlcNAc2 oligosaccharide. However, when MDCK cells are incubated in 1 to 10 mM mannosamine and labeled with (2-/sup 3/H)mannose, the major oligosaccharides associated with the dolichol were Man5GlcNAc2 and Man6GlcNAc2 structures. Since both of these oligosaccharides were susceptible to digestion by endo-beta-N-acetylglucosaminidase H, the Man5GlcNAc2 must be different in structure than the Man5GlcNAc2 usually found as a biosynthetic intermediate in the lipid-linked oligosaccharides. Since pulse chase studies indicated that the lesion was in biosynthesis, it appears that mannosamine inhibits the in vivo formation of lipid-linked oligosaccharides perhaps by inhibiting the alpha-1,2-mannosyl transferases. Although the lipid-linked oligosaccharides produced in the presence of mannosamine were smaller in size than those of control cells and did not contain glucose, the oligosaccharides were still transferred in vivo to protein. Furthermore, the oligosaccharide portions of the glycoproteins were still processed as shown by the fact that the glycopeptides were of the complex and hybrid types and were labeled with (/sup 3/H)mannose or (/sup 3/H)galactose.
- Research Organization:
- Univ. of Texas Health Science Center, San Antonio
- OSTI ID:
- 6390118
- Journal Information:
- Arch. Biochem. Biophys.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
BIOLOGICAL EFFECTS
GLUCOPROTEINS
BIOSYNTHESIS
GLYCOLIPIDS
ANIMAL CELLS
DOGS
HEXOSAMINES
KIDNEYS
KINETICS
MANNOSE
OLIGOSACCHARIDES
TRITIUM COMPOUNDS
ALDEHYDES
ANIMALS
BODY
CARBOHYDRATES
HEXOSES
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANS
PROTEINS
SACCHARIDES
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques