INFLUENCE OF THE PHOTOSYNTHETIC PATHWAY ON THE HYDROGEN ISOTOPIC PROFILE OF GLUCOSE

Ben-Li Zhang1, Isabelle Billault1, Xiaobao Li1, Francoise Mabon1, Gerald Remaud2, Maryvonne L. Martin2

1Laboratoire d’Analyse Isotopigue et Electrochimique de Metabolismes, CNRS UMR 6006 Universite de Nantes, 2 rue de la Houssiniere, 44322 Nantes, France,
2Eurofins Scientific, rue P.A. Bobierre, BP 72304, 44323 Nantes Cedex 3, France


The SNIF-NMR method (site-specific natural isotope fractionation studied by Nuclear Magnetic Resonance) was used to examine the isotopic profile of glucoses derived from plants with different photosynthetic pathways. It is shown that the type of photosynthetic metabolism, either C3 (beet-root, orange, grape), C4 (maize, sugar-cane) or CAM (pineapple), exerts a strong influence on the deuterium distribution in the sugar molecules. The isotopic profile also depends, secondarily, on the physiological status of the precursor plant. Consequently, the isotopic fingerprint of glucose may be a rich source of information in mechanistic comparisons of metabolic pathways. Moreover, from an analytical point of view, it may provide complementary criteria with respect to the ethanol probe for origin inference of sugars.