UDP-GlcA

The resulting disaccharide derivative (26) accepts from UDP-GlcA the a-D-glucosyluronic group present in side chains of the polysaccharide. Only after its transfer does incorporation of another D-galactosyl residue of the... 

The type 3 capsular polysaccharide199 (38) was found375,376 to be efficiently formed from UDP-Glc and UDP-GlcA. Under optimal conditions, >90% of the glycosyl groups of the glycosyl nucleotides was incorporated into polymer identified by immunochemical methods. 

Photoaffinity analogs of UDP-Xyl and UDP-GlcA have been chemo-enzymatically synthesized for a covalent derivatization and 32P-labeling of membrane-bound glycosyltransferases and nucleotide sugar metabolizing enzymes (Table 4) [322, 325, 359, 360],... 

Fig. 2. UDP-Glc dehydrogenase activity in control and transgenic alfalfa plants. Stem internodes of uniform age from greenhouse-grown plants were assayed for production of UDP-GlcA. Activity is expressed as percentage of the untransformed control Regen-SY. Plant lines in bold were selected for field testing.

HA synthase from Streptococcus equisimilis was employed for milligram-scale synthesis of HA (109). In this reaction system, UDP-sugars (UDP-GlcA and UDP-GlcNAc) were effectively regenerated by the catalyses of several enzymes, synthetic HA was produced in 90% yield. In addition, mutated HA synthase from Type A Pasteurella multocida (PmHAS 1-703 aa) was recently used for the stepwise synthesis of HA, which has a monodispersed molecular mass of up to 20 sugar units (110). 

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