UNIGE document Scientific Article
previous document  unige:2397  next document
add to browser collection
Title

Determination of 13C isotopic enrichment of valine and threonine by GC-C-IRMS after formation of the N(O,S)-ethoxycarbonyl ethyl ester derivatives of the amino acids

Authors
Faure, Magali
Breuille, Denis
Fay, Laurent-Bernard
Published in Analytical and Bioanalytical Chemistry. 2007, vol. 388, no. 4, p. 909-918
Abstract We describe a new method of assessing, in a single run, (13)C isotopic enrichment of both Val and Thr by gas chromatography-combustion-isotope-ratio mass spectrometry (GC-C-IRMS). This method characterised by a rapid one-step derivatisation procedure performed at room temperature to form the N(O,S)-ethoxycarbonyl ethyl ester derivatives, and a polar column for GC. The suitability of this method for Val and Thr in in-vivo samples (mucosal hydrolysate) was demonstrated by studying protein metabolism with two tracers ((13)C-valine or (13)C-threonine). The intra-day and inter-day repeatability were both assessed either with standards or with in-vivo samples at natural abundance and at low (13)C isotopic enrichment. For inter-day repeatability CVs were between 0.8 and 1.5% at natural abundance and lower than 5.5% at 0.112 and 0.190 atom% enrichment for Val and Thr, respectively. Overall isotopic precision was studied for eleven standard amino acid derivatives (those of Val, Ala, Leu, Iso, Gly, Pro, Asp, Thr, Ser, Met, and Phe) and was assessed at 0.32 per thousand. The (13)C isotopic measurement was then extended to the other amino acids (Ala, Val, Leu, Iso, Gly, Pro, Thr, and Phe) at natural abundance for in-vivo samples. The isotopic precision was better than 0.002 atom% per amino acid (for n = 4 rats). This analytical method was finally applied to an animal study to measure Thr utilization in protein synthesis.
Keywords Amino Acids/chemistryAnimalsCarbon Isotopes/chemistryEsters/chemistryEthyl Ethers/chemistryGas Chromatography-Mass Spectrometry/methodsIntestinal Mucosa/chemistry/metabolismMaleProtein BiosynthesisRatsRats, Sprague-DawleyReproducibility of ResultsSensitivity and SpecificityThreonine/analysisTime FactorsValine/analysis
Identifiers
PMID: 17468859
Full text
Structures
Citation
(ISO format)
GODIN, Jean-Philippe et al. Determination of 13C isotopic enrichment of valine and threonine by GC-C-IRMS after formation of the N(O,S)-ethoxycarbonyl ethyl ester derivatives of the amino acids. In: Analytical and Bioanalytical Chemistry, 2007, vol. 388, n° 4, p. 909-918. https://archive-ouverte.unige.ch/unige:2397

224 hits

3 downloads

Update

Deposited on : 2009-08-10

Export document
Format :
Citation style :