Abstract:
The ubiquitous isoprenoid phytol was isolated from a range of algae, terrestrial plants
and a bacterium and its two terminal carbon atoms were quantitatively removed by
chemical oxidation. The product, 6,10,14-trimethylpentadecan-2-one, was depleted in
13C by 1-4‰ relative to the parent phytol. This difference is significant, and indicates
that the pathway for biosynthesis of phytol induces substantial intramolecular stable
carbon isotopic fractionations. The nature and magnitude of the fractionations suggest
strongly that it is associated both with the biosynthesis of isopentenyl pyrophosphate
via the 2-C-methylerythritol-4-phosphate pathway and with the formation of
carotenoids and phytol from geranyl-geraniolphosphate. As a result of these large,
intramolecular isotopic differences, diagenetic products formed by loss of C, such as
pristane, may be naturally depleted in 13C by several permil relative to phytane.
Description:
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 39 (2008): 135-146, doi:10.1016/j.orggeochem.2007.09.002.
