Biosynthesis oligosaccharides

Mahal, L.K., Yarema, K.J., and Bertozzi, C.R. (1997) Engineering chemical reactivity on cell surfaces through oligosaccharide biosynthesis. Science 276, 1125-1128. 

Gonzalez, D. S., Karaveg, K., Vandersall-Naim, A S., Lai., A., and Moremen. K. W. (1999). Identification, expressetion, and characterization of a cDNA encoding human endoplasmic reticulum mannosidase I, the enzyme that catalyzes the first mannose trimming step in mammalian Asn-linked oligosaccharide biosynthesis../. Biol. Chem., 274, 21375-21386. 

Glycosyl transferases are essential enzymes for oligosaccharide biosynthesis. These enzymes can be classified as enzymes of the Leloir pathway and those of the non-Leloir pathway. The glycosyltransferases of the Leloir pathway are involved in the biosynthesis of most iV-linked... 

Velasco,). and Adrio, ).L. (2002) Microbial enzymes for food-grade oligosaccharide biosynthesis, in Microorganisms for Health Care, Food and Enzyme Production (ed. ).L Barredo), Research Signpost, Kerala, India. 

Ziegler C, Mersmann G. Influence of effectors of the complex-type-oligosaccharide biosynthesis on the formation of proteok-eratan sulfate in bovine cornea. Biochim. Biophys. Acta 1984 799(3) 203-208. 

Fig. 3. Representative pathway for the biosynthesis of Asn-linked oligosaccharide. Biosynthesis starts in the rough endoplasmic reticulum and proceeds through the cis-, medial-, and trans-Golgi apparatus, before glycoprotein is secreted. Some of the enzymes involved are oligosaccharyl transferase (OST) a-glucosidase I II (aG I II) ER-mannosidase (aM) a-mannosidase I II (aM I II) N-acetylglucosaminyl transferase I II (GnT I II) fucosyl transferase (FucT) galactosyl transferase (GalT) sialyl transferase (ST). n-Gn O-Man -Glc V-Fuc A-Gal O-SA (adopted from [40])...

In transfected mammalian cells inhibition of N-glycan addition by treatment with tunicamycin prevented secretion of factor VIII, whereas treatment with an inhibitor of complex oligosaccharide biosynthesis, deoxymannojirimycin, did not affect secretion, although the specific activity of factor VIII was slightly increased [45]. Thus, the presence of complex oligosaccharide was not required for secretion or functional activity of factor VIII. A23187 treatment inhibited addition of serine/threonine (O)-linked glycans to factor VIII. 

This intermediate is unusual for two reasons. First, other intermediates in oligosaccharide biosynthesis involve nucleoside diphosphates (such as UDP-Glucose). Second, CMP-sialic acid is synthesized in the nucleus of animal cells, whereas all other known nucleotide-linked sugars are synthesized in the cytosol. 

For reviews of the enzymes involved in oligosaccharide biosynthesis, see Refs. 3 and 4. 

S ATP + 1,2-diacyl-sn-glycerol <2, 3> (<2>, the enzyme functions to recycle diacylglycerol which is generated largely as a by-product of membrane-derived oligosaccharide biosynthesis [2] <3>, the enzyme may regulate the intracellular concentration of diacylglycerol [3]) (Reversibility <2, 3> [2, 3]) [2, 3]... 

Chui D, Oh-Eda M, Liao YF, Panneerselvam K, Lai A, Marek KW, Freeze HH, Moremen KW, Fukuda MN, Marth JD. Alpha-mannosidase-II deficiency results in dyserythropoiesis and unveils an alternate pathway in oligosaccharide biosynthesis. Cell 1997 90 157-167. 

Krylov, S. N., Arriaga, E. A., Chan, N. W., Dovichi, N. J. and Palcic, M. M. Metabolic cytometry monitoring oligosaccharide biosynthesis in single cells by capillary electrophoresis. Anal Biochem, 283,133, 2000. 

Taking into account that enzymatic methods basically mimic in vitro the natural pathways of oligosaccharide biosynthesis, a reasonable short-cut is the production of the oligosaccharide in a living recombinant organism e.g. Escherichia coli). Unfortunately this task is not simple to accomplish, because of the characteristics of the biosynthetic machinery involved in the synthesis of the desired products. Production in E. coli of active eukaryotic GTs in suitable amounts is not always possible or requires eonsiderable effort for reasons that are not well understood. This problem can be overcome by use of homologous enzymes from prokaryotic organisms. 

Consequences of Genetic Defects in Oligosaccharide Biosynthesis and Catabolism... 

Ellies, L. G., S. Tsuboi, B. Petryniak, J. B. Lowe, M. Fukuda, and J. D. Marth, Core 2 oligosaccharide biosynthesis distinguishes between selectin ligands essential for leukocyte homing and inflammation, Immunity, 1998, 9, 881-890. 

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