Galactose, biosynthesis

Optimizing Gaiactosylation of Recombinant Proteins by Metabolically Engineering Galactose Biosynthesis... 

Overexpression of selected enzymes involved in galactose biosynthesis, either independently or collectively as an entire metabolic pathway, may be a route to increased levels of galactosylation in CHO cells. These include the UDP-glucose-4-epimerase [36], the phosphoglucomutase [43], and the UDP-glucose pyrophosphor-ylase [44] and the UDP-galactose transferase [45]. All of the genes for these enzymes have been isolated from either mammalian or microbial sources. 

In all plants and most animals, L-ascorbic acid is produced from D-glucose (4) and D-galactose (26). Ascorbic acid biosynthesis in animals starts with D-glucose (4). In plants, where the biosynthesis is more compHcated, there are two postulated biosynthetic pathways for the conversion of D-glucose or D-galactose to ascorbic acid. 

By analogy with the biosynthesis of L-ascorbic acid and with other oxidation-reduction enzyme systems, it seems likely that D-galactose is oxidized to D-galacturonic acid (XXIII) on reduction at Cl, this yields L-galactonic acid (XXIV), the 1,5-lactone (XXV) of which, on reduction at Cl, would give L-galactose (XXII). 

DGBP Lactalbumins Lysozymes Galactose activation (369) Lactose biosynthesis Catalyze degradation of peptidoglycan, e.g. of bacterial cell walls (370,371)... 

Laing, W. A., Wright, M. A., Cooney, J., Bulley, S. M. (2007). The missing step of the L-galactose pathway of aseorbate biosynthesis in plants, an L-galactose guanyltransferase, increases leaf ascorbate content. Proceedings of the National Academy of Sciences of the United States of America, 104(22), 9534-9539. 

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