Premium
Natural Deuterium Distribution in Fatty Acids Isolated from Peanut Seed Oil: A Site‐Specific Study by Quantitative 2 H NMR Spectroscopy
Author(s) -
Duan JiaRong,
Billault Isabelle,
Mabon Françoise,
Robins Richard
Publication year - 2002
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/1439-7633(20020802)3:8<752::aid-cbic752>3.0.co;2-g
Subject(s) - chemistry , fractionation , deuterium , nuclear magnetic resonance spectroscopy , linoleic acid , fatty acid , transesterification , deuterium nmr , spectroscopy , peanut oil , gas chromatography , chromatography , organic chemistry , catalysis , raw material , physics , quantum mechanics
Quantitative 2 H NMR spectroscopy has been used to measure the distribution of deuterium at natural abundance in long‐chain fatty acids extracted from the same vegetable oil. Peanut seed oil was selected, due to its suitable oleic and linoleic acid content. The methyl esters of the fatty acids were prepared by transesterification and isolated by modified argentation column chromatography on silica. In order to measure the natural isotopic fractionation of deuterium (D) at the maximum number of positions, the purified methyl oleate and methyl linoleate were chemically cleaved and the (D/H) i values determined by quantitative 2 H NMR spectroscopy. It was thus possible to demonstrate that fractionation in deuterium occurs during the desaturation of oleate to linoleate. Furthermore, the previously observed distribution of deuterium at the sites of desaturation is confirmed, as is the alternating pattern of (D/H) i , which relates to the origin of the pertinent hydrogen atoms. The data obtained are discussed in terms of the kinetic isotopic effects intrinsic to the enzymes—synthetases and desaturases—involved in the biosynthesis of fatty acids.