Uridine diphosphate-galactose

Most nucleotide sugars are formed in the cytosol, generally from reactions involving the corresponding nucleoside triphosphate. GMP-sialic acids are formed in the nucleus. Formation of uridine diphosphate galactose (UDP-Gal) requires the following two reactions in mammahan tissues ... 

UDPGal = UDPG Uridine diphosphate galactose 4-epimerase... 

Isselbacher, K. J., A mammalian uridine diphosphate galactose pyrophos-phorylase. J. Biol. Chetn. 232, 429-444 (1958). 

Seyama, Y., Kalckar, H. M. Interaction between uridine diphosphate galactose and uridine diphosphate galactose 4-epimerase from Escherichia coli. Biochemistry 11, 40—44 (1972). 

Wee, T. G., Frey, P. A. Studies on the mechanism of action of uridine diphosphate galactose 4-epimerase. Substate dependent reduction by sodium borohydride. J. Biol. Chem. 248, 33—40 (1973). 

Ketley, J. N., Schellenberg, K. A. Substrate stereochemical requirements in the reductive inactivation of uridine diphosphate galactose 4-epimerase by sugar and 5 -uridine monophosphate. Biochemistry 12, 315—320 (1973). 

It contains the attenuated strain Ty21a of Salmonella typhi. The attenuation is due to the absence of enzyme uridine diphosphate galactose-4-epimerase which is essential for the production of the lipopolysaccharide O antigen. The absence of this enzyme makes Ty21a highly immunogenic. 

Bergren WR, Ng WG, Donnel GN (1973) Uridine diphosphate galactose-4-epimerase in human and other mammalian haemolysates. Biochim Biophys Acta 313 464-472... 

Gitzelmann R, Steinmann B, Mitchell B, Haigis E (1976) Uridine diphosphate galactose 4 -epimerase deficiency. IV. Report of eight cases in three families. HelvPaediatr Acta 31 441-452... 

Ng WG, Donnel GN, Hodgman JE, Bergren WR (1967) Differences in uridine diphosphate galactose-4-epimerase between haemolysates of newborns and of adults. Nature 214 283-284... 

Kuhn, N. J. and White, A. 1976. Evidence for specific transport of uridine diphosphate galactose across the Golgi membrane of rat mammary gland. Biochem. J. 154, 243-244. 

Uridine diphosphate galactose lactosylceramide galactosyltransferase activity in cultured normal and familial hypercholesterolemic human fibroblasts... 

UDP uridine diphosphate UDP-galactose uridine diphosphate galactose UDP-glucose uridine diphosphate glucose UMP uridine monophosphate UTP uridine triphosphate Val valine... 

Uridine diphosphate galactose (109) was prepared using seven enzymes involved in three biosynthetic pathways, immobilised on super-bead columns. This method, which converted 50% of uracyl monophosphate into UDP-galactose (109), was superior to the solution approach as enzyme stability was improved. To study the biosynthesis of the pseudosaccaharide acarbose, thymidine 5 -diphospho-4-amino-4,6-dideoxy-a-D-glucopyranose(110) was synthesised from galactose in sixteen steps. 

Under appropriate experimental conditions, the blood type of red blood cells can be changed by addition or removal of specific carbohydrate residues. For example, when type O red blood cells are incubated with the galactose donor substrate (uridine diphosphate galactose) and the specific a-galactosyltransferase enzyme, they are... 

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