GDP-glucose

The mechanism of bacterial cellulose production has been extensively studied by many research groups. Notably, some important differences exist between its production in bacteria and in plants. For example, bacterial cellulose is produced in the culture medium, whereas plant cellulose is synthesized as a cell-wall construction. Also, in bacteria the precursor of cellulose is UDP-glucose, whereas in plants it is GDP-glucose. 

Cell lysates from mutant strains of X. campestris were incubated with radiolabelled UDP[14C] glucose or GDP[,4C] mannose, the other sugar nudeotide substrates being unlabelled. The reaction mixture was then divided into lipid and soluble fractions. Where would you expect the radiolabel to be found and what produd, if any, would you expert from strains with defidendes in the following genes ... 

Incretins gut hormones that increase glucose-stimulated insulin secretion GLP-1 glucagon-like peptide-1 GDP Gastric inhibitory peptide or glucose-dependent insulino-tropic peptide... 

GDP) was isolated. It was characterized as being released by the duodenum following an oral glucose load and increasing glucose-stimulated insulin secretion. However, this pqDtide was not able to account fully for the... 

The incorporation and metabolism of 2-deoxy-2-fluoro-D-[ H]glucose and -D-[ H]mannose in yeast and chick-embryo cells has been studied. 2-Deoxy-2-fluoro-D-glucose, 2-deoxy-2-fluoro-D-mannose, and their GDP and UDP derivatives were found to interfere with protein (involving that of... 

Figure 47-7. Pathway of biosynthesis of dolichol-P-P-oligosaccharide. The specific linkages formed are indicated in Figure 47-8. Note that the first five internal mannose residues are donated by GDP-mannose, whereas the more external mannose residues and the glucose residues are donated by dolichol-P-mannose and dolichol-P-glucose. (UDP, uridine diphosphate Dol, dolichol P, phosphate UMP, uridine monophosphate GDP, guanosine diphosphate M, mannose G, glucose.)...

Table I. The influence of the presence of exogenous GDPMan on the synthesis of a mixed /3l — 3, 1 — 4 glucan from GDPGlc by a membrane preparation from pine stem tissue. Measurements were made from the incorporation of radioactive glucose from GDP[U-14C]Glc (18). (- indicates that no glucan carrying a /3l — 3 linkage was formed.)...

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