13C-glucose

Sibson, N. R., Mason, G. E, Shen, J. etal. In vivo 13C NMR measurement of neurotransmitter glutamate cycling, anaplerosis and TCA cycle flux in rat brain during [2-13C]glucose infusion. /. Neurochem. 76 975-978, 2001. 

Figure 14. Principle for measuring bidirectional fluxes by 13C metabolic flux analysis. In a carbon labeling experiment, 1 13C glucose is provided in the medium, and the culture is grown until a steady state is reached. Glucose can either go directly via the hexose phosphate pool (Glu 6P and Fru 6P) into starch, resulting in labeling hexose units of starch only at the Cj position, or it can be cleaved to triose phosphates (DHAP and GAP), from which hexose phosphates can be resynthesized, which will result in 50% labeling at both the Ci and the C6 position (assuming equilibration of label by scrambling at the level of triose phosphates). From the label in the hexose units of starch, the steady state fluxes at the hexose phosphate branchpoint can be calculated for example, if we observe 75% label at the Ci and 25% at the C6 position, the ratio of vs to V7 must have been 1 to 1. All other fluxes can be derived if two of the fluxes of Vi, V6, and V7 are known (e.g., V2 vi V3 V5 + v6).

U. Sauer, N. Zamboni, and E. Fischer, FiatFlux a software for metabolic flux analysis from 13C glucose experiments. BMC Bioinform. 6, e209 (2005). 

A biosynthetic study of the 18-carbon chain skeleton of broussonetines was reported [38]. To verify the biosynthetic route of these alkaloids, the plant was grown on an aseptic medium and the enriched l3C of the isolated alkaloids was analyzed by NMR after feeding with [l-13C]glucose. The labeling pattern of broussonetine J (27) obtained... 

Gustafsson J, Eriksson J, Marcus C. Glucose metabolism in human adipose tissue studied by 13C-glucose and microdialysis. Scandinavian Journal of Clinical and Laboratory Investigation 2007, 67, 155-164. 

Scheme 5.3 Formation of proline- and hydroxyproline-specific heterocyclic volatiles from [1 -13C glucose via 3-deoxyglucosone223...

Scheme 5.5 Formation of 50% labelled 2-acetyl-l-pyrroline from [1 -13C]glucose and proline via -deoxy-2,2-diketose and dihydrodiacetylformoin223...

As expected, [2-13C]glucose leads to the labelling of the methylpyrazines almost exclusively in the quaternary C atoms. There was evidence of a small amount (about 5%) of label in the methine groups and this was attributed to retroaldolisation of glucose or the glucosylamine (see ref. 92). 

Cysteine can undergo the Strecker degradation, transamination, and -elimination, as shown by Tressl et al.247 using [1- or 6-13C]glucose (equimolar aqueous solution, 160 °C, 1.5 h). 2-Furylmethanethiol (T 0.005 ppb), very important in providing the aroma of roasted coffee and roasted meat, is formed as shown in Scheme 5.14 from [l-13C]glucose via the 3-deoxy-l,2-dicarbonyl, which loses... 

R. Tressl, B. Helak, E. Kersten, and D. Rewicki, Formation of praline- and hydroxyproline-specific Maillard products from [l-13C]glucose, J. Agric. Food Chem., 1993, 41, 547-553. 

Fig. 5.6. Proton decoupled 13C n.m.r. spectrum at 75.47 MHz of the excretory products of Hymenolepis dimimta fed D-[6-13C]glucose. p.p.m., parts per million. (After Blackburn et al, 1986.)...

According to the reaction scheme shown in Fig. 4, pyruvate and, therefore, alanine and lactate, formed from degradation of l-13C-glucose should only be... 

Exploration of geldanomycin (150) biosynthesis with D-[6-13C]glucose has revealed that the C7N unit of this antibiotic has a similar origin (labelling of C-17 and C-21 cf. nybomycin above), although shikimic acid (144) itself was a poor precursor.133 Similar observations were made on shikimic acid incorporation in the... 

It should be noted, finally, that in the experiment with [6-13C]glucose more extensive labelling of (150) than already mentioned was observed, but the labelling... 

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