UDP-GalNAc

N-Acetylgalactosamine Aminohexose GalNAc UDP-GalNAc Present in both N- and 0-linked glycoproteins. 

A) Human GalNAc-l-P kinase, (B) human UDP-GalNAc pyrophosphorylase, (C) bovine polypeptide GalNAc-transferase, (D) rabbit creatine kinase and (E) inorganic pyrophosphatase. 

UDP-GalNAc From UDP-Glc and Gal-l-P with UDP-glucose galactosylphosphate uridyl-transferase... 

Uridine-5 -diphosphate galactose (UDP-Gal) Uridine-5 -diphosphate glucosamine (UDP-GlcNAc) 1 Uridine-5 -diphosphate galactosamine (UDP-GalNAc) j 4.5-180 18 2, 3 2... 

It seems possible that a block mechanism also operates in the assembly of the chain of polysaccharide 42, present in the cell wall of Bacillus cereus.124 In this case, formation of the polymer from a-GlcNAc-pp-Bpr, UDP-ManNAc, UDP-GalNAc, and UDP-Glc was observed.74... 

Glycoproteins in the secretory pathway receive GalNac in O-glycosidic linkage from UDP-GalNAc via a transferase that acts directly on certain Ser or Thr residues of proteins. 

Treatment GM3 UDP GalNAc N-acetylgalactos-aminy1trans fe rase GM2 UDP Gal Galactosyl-transferase... 

N4TG1 cells were exposed to fentanyl (lOpM) for varying periods of time and the homogenates assayed for GM3 hexosaminyltransferase activity with UDP GalNAc as described in the text... 

Fig. 14. Salvage pathways of nucleotide sugars. L-fucose (11), (3-L-fucose-l-phosphate (12), GDP-p-L-fucose (13), A fucokinase (EC 2.7.1.52), B GDP-Fuc pyrophosphorylase (EC 2.7.7.30). D-galactose (14), a-D-galactose-l-phosphate (15), UDP-a-D-galactose (16), C galactokinase (EC 2.7.1.6), D UDP-Gal pyrophosphorylase. IV-acetyl-D-galactosamine (17), Al-acetyl-a-D-galactosamine-l-phosphate (18), UDP-lV-acetyl-a-D-galactosamine (19), E IV-acetyl-galactosamine kinase (EC 2.7.1. ), F UDP-GalNAc pyrophosphorylase (EC 2.7.7. )...

A de novo synthesis of GDP-Fuc (13), UDP-Gal (16) and UDP-GalNAc (19) by isolated enzymes of the salvage pathways (see Fig. 14) has not yet been described. A crude extract from porcine submaxillary glands gave a yield of 80% for the synthesis of p-L-fucose-1-phosphate (12), but the synthesis of 13 was less successful with a yield of 20% [312]. The main pathways for 16 and 19 involve 4-epimerases (Table 4 and Fig. 14) which are not suitable for preparative synthesis due to their unfavourable equilibrium constants [347, 348], An alternative is Gal-l-P uridyltransferase which is only specific for Gal-l-P and GalNH2-l-P (Table 4). 

Key Words Haemophilus infuenzae P-l,3-iV-acetylgalactosaminyltransferase enzymatic synthesis globotetraose LgtD lipopolysaccharide UDP-GalNAc complex carbohydrates glyconjugates. 

To obtain sufficient material for structural analysis, a preparative reaction was conducted with globotriose as acceptor. The reaction was optimized so that the substrate, UDP-GalNAc, was converted completely to the product. The high yield simplified the isolation of oligosaccharide product for further analysis. 

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