Overview Of Metabolic Substrate Engineering

The complex glycoconjugates expressed on eukaryotic cell surfaces (Figs. 3-8) comprise primarily 10 monosaccharides: Glc, Gal, Man, Fuc, GlcN, GlcNAc, GalNAc, Xyl, GlcUA, and sialic acid (Neu5Ac). These sugars can be biosynthesized de novo within a cell, often from Glc; or, in many cases, key metabolic intermediates can be supplied exogenously to a cell. The pathways for these interconversions are summarized in Figure 9 [33-36]. If the enzymes in these biosynthetic pathways could tolerate unnatural substrates, subtle modifications, such as replacement of a hydroxyl group with a hydrogen atom or halogen, could be introduced into cell surface gly-cans. This possibility attracted the attention of many groups interested in understanding how specific carbohydrate structures dictate molecular and cellular interactions.

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Biochemistry Common Core Oligosaccharide

Figure 3 The oligosaccharide Glc3Man9GlcNA2 is a common precursor in the biosynthesis of the three types of N-linked 4 oligosaccharides. 01

Figure 3 The oligosaccharide Glc3Man9GlcNA2 is a common precursor in the biosynthesis of the three types of N-linked 4 oligosaccharides. 01

Figure 4 Examples of the three types of N-linked oligosaccharides found in human a-galactosidase A. Their common core structure is shown in gray.

Figure 4 Examples of the three types of N-linked oligosaccharides found in human a-galactosidase A. Their common core structure is shown in gray.

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