Selective conversion of plasma glucose into CO2 by Saccharomyces cerevisiae for the measurement of 13C abundance by isotope ratio mass spectrometry: proof of principle

Media type: E-Article
Title: Selective conversion of plasma glucose into CO2 by Saccharomyces cerevisiae for the measurement of 13C abundance by isotope ratio mass spectrometry: proof of principle
Contributor: Rembacz, Krzysztof P.; Faber, Klaas Nico; Stellaard, Frans
imprint: Wiley, 2007
Published in: Rapid Communications in Mass Spectrometry
Language: English
DOI: 10.1002/rcm.3178
ISSN: 0951-4198; 1097-0231
Keywords: Organic Chemistry ; Spectroscopy ; Analytical Chemistry
Origination:
Footnote:
Description: <jats:title>Abstract</jats:title><jats:p>To study carbohydrate digestion and glucose absorption, time‐dependent <jats:sup>13</jats:sup>C enrichment in plasma glucose is measured after oral administration of naturally occurring <jats:sup>13</jats:sup>C‐enriched carbohydrates. The isotope enrichment of the administered carbohydrate is low (APE <0.1%) and plasma <jats:sup>13</jats:sup>C glucose measurements are routinely determined with gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) or liquid chromatography/combustion/isotope ratio mass spectrometry (LC/C/IRMS). In this study, plasma glucose was converted into CO<jats:sub>2</jats:sub> by an in‐tube reaction with yeast permitting direct measurement of <jats:sup>13</jats:sup>CO<jats:sub>2</jats:sub> in the headspace. <jats:italic>Saccharomyces cerevisiae</jats:italic> incubated under anaerobic conditions was able to convert sufficient glucose into CO<jats:sub>2</jats:sub> to produce a consistent CO<jats:sub>2</jats:sub> peak in IRMS with little variation in peak area and precise <jats:italic>δ</jats:italic><jats:sup>13</jats:sup>C<jats:sub>PDB</jats:sub> values for corn glucose: −11.40 ± 0.16‰, potato glucose: −25.17 ± 0.13‰, and plasma glucose: −26.29 ± 0.05‰. The measurement showed high linearity (R<jats:sup>2</jats:sup> = 0.999) and selectivity and was not affected by the glucose concentration in the tested range of 5–15 mM. Comparison with GC/C/IRMS showed a good correlation of enrichment data: R<jats:sup>2</jats:sup> > 0.98 for both sources of glucose and plasma samples. Commercially available, instant dried baker's yeast was qualitatively and quantitatively comparable with freshly prepared yeast: R<jats:sup>2</jats:sup> > 0.96, slope 1.03 and 1.08 for glucose solutions and plasma, respectively. Thus, yeast conversion of plasma glucose into CO<jats:sub>2</jats:sub> and <jats:sup>13</jats:sup>C measurement applying a breath <jats:sup>13</jats:sup>CO<jats:sub>2</jats:sub> analyzer is an inexpensive, simple and equally accurate alternative to the more expensive and laborious GC/C/IRMS and LC/C/IRMS measurements. Copyright © 2007 John Wiley & Sons, Ltd.</jats:p>

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