Mass Isotopomer Analysis of Nucleosides Isolated from RNA and DNA Using GC/MS

2014 ◽  
Vol 87 (1) ◽  
pp. 617-623 ◽  
Author(s):  
Ines Miranda-Santos ◽  
Silvia Gramacho ◽  
Marta Pineiro ◽  
Karla Martinez-Gomez ◽  
Michel Fritz ◽  
...  
Keyword(s):  
Isotopomer Analysis ◽  
Rna And Dna ◽  
Mass Isotopomer

Mass isotopomer study of the nonoxidative pathways of the pentose cycle with [1,2-13C2]glucose

1998 ◽  
Vol 274 (5) ◽  
pp. E843-E851 ◽  
Author(s):  
Wai-Nang Paul Lee ◽  
Laszlo G. Boros ◽  
Joaquim Puigjaner ◽  
Sara Bassilian ◽  
Shu Lim ◽  
...  
Keyword(s):  
Pentose Phosphate ◽  
Gas Chromatography Mass Spectrometry ◽  
Hep G2 ◽  
Tracer Method ◽  
Human Hepatoma Cells ◽  
Glucose Flux ◽  
Isotopomer Analysis ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Mass Isotopomer

We present a single-tracer method for the study of the pentose phosphate pathway (PPP) using [1,2-13C2]glucose and mass isotopomer analysis. The metabolism of [1,2-13C2]glucose by the glucose-6-phosphate dehydrogenase, transketolase (TK), and transaldolase (TA) reactions results in unique pentose and lactate isotopomers with either one or two13C substitutions. The distribution of these isotopomers was used to estimate parameters of the PPP using the model of Katz and Rognstad (J. Katz and R. Rognstad. Biochemistry 6: 2227–2247, 1967). Mass and position isotopomers of ribose, and lactate and palmitate (products from triose phosphate) from human hepatoma cells (Hep G2) incubated with 30% enriched [1,2-13C2]glucose were determined using gas chromatography-mass spectrometry. After 24–72 h incubation, 1.9% of lactate molecules in the medium contained one 13C substitution ( m 1) and 10% contained two 13C substitutions ( m 2). A similar m 1-to- m 2ratio was found in palmitate as expected. Pentose cycle (PC) activity determined from incubation with [1,2-13C2]glucose was 5.73 ± 0.52% of the glucose flux, which was identical to the value of PC (5.55 ± 0.73%) determined by separate incubations with [1-13C] and [6-13C]glucose.13C was found to be distributed in four ribose isotopomers ([1-13C]-, [5-13C]-, [1,2-13C2]-, and [4,5-13C2]ribose). The observed ribose isotopomer distribution was best matched with that provided from simulation by substituting 0.032 for TK and 0.85 for TA activity relative to glucose uptake into the model of Katz and Rognstad. The use of [1,2-13C2]glucose not only permits the determination of PC but also allows estimation of relative rates through the TK and TA reactions.

Mass Isotopomer Analysis

1994 ◽  
Vol 27 (1) ◽  
pp. 351
Author(s):  
Robert R. Wolfe
Keyword(s):  
Isotopomer Analysis ◽  
Mass Isotopomer

Rates of Gluconeogenesis (GNG) in Rat Livers Perfused with [U- 13 C 3 ]lactate and [U- 13 C]pyruvate: Estimating Isotope Dilution by Mass Isotopomer Analysis

1994 ◽  
Vol 27 (1) ◽  
pp. 375-376
Author(s):  
C. Des Rosiers ◽  
L. Di Donato ◽  
B. Comte ◽  
A. Laplante ◽  
C. Marcoux ◽  
...  
Keyword(s):  
Isotope Dilution ◽  
Isotopomer Analysis ◽  
Rat Livers ◽  
Mass Isotopomer

scholarly journals Metabolomic and Mass Isotopomer Analysis of Liver Gluconeogenesis and Citric Acid Cycle

2008 ◽  
Vol 283 (32) ◽  
pp. 21988-21996 ◽  
Author(s):  
Lili Yang ◽  
Takhar Kasumov ◽  
Rajan S. Kombu ◽  
Shu-Han Zhu ◽  
Andrea V. Cendrowski ◽  
...  
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Acid Cycle ◽  
Isotopomer Analysis ◽  
Mass Isotopomer

scholarly journals The use of uniformly labelled substrates and mass isotopomer analysis to study intermediary metabolism

1994 ◽  
Vol 53 (2) ◽  
pp. 345-354 ◽  
Author(s):  
Heiner K. Berthold ◽  
Linda J. Wykes ◽  
Farook Jahoor ◽  
Peter D. Klein ◽  
Reeds Peter J.
Keyword(s):  
Intermediary Metabolism ◽  
Isotopomer Analysis ◽  
Mass Isotopomer

Metabolism of γ-hydroxybutyrate in perfused rat livers

2012 ◽  
Vol 444 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Guo-Fang Zhang ◽  
Sushabhan Sadhukhan ◽  
Rafael A. Ibarra ◽  
Stephanie M. Lauden ◽  
Chia-Ying Chuang ◽  
...  
Keyword(s):  
Date Rape ◽  
Succinic Semialdehyde ◽  
Acetyl Coa ◽  
Parallel Processes ◽  
Multiple Processes ◽  
Isotopomer Analysis ◽  
Pathway Discovery ◽  
Date Rape Drug ◽  
Rat Livers ◽  
Mass Isotopomer

GHB (γ-hydroxybutyrate) is both a neurotransmitter and a drug of abuse (date-rape drug). We investigated the catabolism of this compound in perfused rat livers. Using a combination of metabolomics and mass isotopomer analysis, we showed that GHB is metabolized by multiple processes, in addition to its previously reported metabolism in the citric acid cycle via oxidation to succinate. A substrate cycle operates between GHB and γ-aminobutyrate via succinic semialdehyde. Also, GHB undergoes (i) β-oxidation to glycolyl-CoA+acetyl-CoA, (ii) two parallel processes which remove C-1 or C-4 of GHB and form 3-hydroxypropionate from C-2+C-3+C-4 or from C-1+C-2+C-3 of GHB, and (iii) degradation to acetyl-CoA via 4-phosphobutyryl-CoA. The present study illustrates the potential of the combination of metabolomics and mass isotopomer analysis for pathway discovery.

Gluconeogenesis and the Cori cycle in 12-, 20-, and 40-h-fasted humans

1998 ◽  
Vol 275 (3) ◽  
pp. E537-E542 ◽  
Author(s):  
Joseph Katz ◽  
John A. Tayek
Keyword(s):  
Blood Glucose ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Glucose Production ◽  
Plasma Glucose Concentration ◽  
Prolonged Fasting ◽  
Cori Cycle ◽  
Isotopomer Analysis ◽  
Mass Isotopomer

Six subjects were infused with [U-13C]glucose (0.03–0.05 mg ⋅ kg−1 ⋅ min−1) starting 8–9 h after a meal, and the production of glucose, the recycling of glucose (the Cori cycle), the dilution of glucose by unlabeled carbon into the hepatic lactate-pyruvate pool, and gluconeogenesis were determined in these fasted volunteers by use of mass isotopomer analysis and equations previously described [J. A. Tayek and J. Katz. Am. J. Physiol.272 ( Endocrinol. Metab. 35): E476–E484, 1997]. A primed continuous 11-h infusion was started at 6:00 AM, and the above parameters were calculated after 3 h (for the 12-h fast) and at the end of the infusion (for the 20-h fast). Another group of five subjects was fasted for 40 h, and the above parameters were calculated as before. At 12, 20, and 40 h of fasting, respectively, blood glucose was 93 ± 2, 83 ± 2, and 71 ± 2 (SE) mg/dl; glucose production was 2.3, 1.8, and 1.77 mg ⋅ kg−1 ⋅ min−1; the recycling of labeled carbon was 8, 15, and 15%, and that of glucose molecules (Cori cycle) was 18, 35, and 36%; the contribution of gluconeogenesis to glucose production was 41, 71, and 92% or 0.96, 1.29, and 1.64 mg ⋅ kg−1 ⋅ min−1; and the contribution of other sources to glucose production was 1.37, 0.53, and 0.15 mg ⋅ kg−1 ⋅ min−1. The recycling of glucose is important in prolonged fasting for the maintenance of plasma glucose concentration. We demonstrate here that gluconeogenesis can be easily measured and that it accounts for ∼90% of glucose production after a 40-h fast.

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