SREL Reprint #3034

Selenomethionine Biotransformation and Incorporation into Proteins along a Simulated Terrestrial Food Chain

Jason M. Unrine1, Brian P. Jackson2, and William A. Hopkins3

1Savannah River Ecology Laboratory, The University of Georgia, Aiken, SC
2Departments of Chemistry and Earth Sciences, Dartmouth College, Hanover, NH
3Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA

Abstract: Selenium is an essential trace element in vertebrates, but there is a narrow concentration range between dietary requirement and toxicity threshold. Although a great deal is known about the biochemistry of Se from a nutritional perspective, considerably less attention has been focused on the specific biochemistry of Se as an environmental toxicant. Recent advances in hyphenated analytical techniques have provided the capability of quantifying specific chemical forms of Se in biological tissues as well as the distribution of Se among macromolecules. We applied liquid chromatography coupled to inductively coupled plasma mass spectrometry to investigate biotransformations of selenomethionine along a simulated terrestrial food chain consisting of selenomethionine exposed crickets (Acheta domesticus) fed to western fence lizards (Sceloporus occidentalis). Evidence was obtained for selenomethionine biotransformation as well as for sex-specific differences in the metabolism of Se compounds and their subsequent incorporation into proteins in the lizard. The results demonstrate the complexities involved in trophic transfer of Se due to the potential for extensive biotransformation and the species- and even sex-specific nature of these biotransformations.

SREL Reprint #3034

Unrine, J. M., B. P. Jackson, and W. A. Hopkins. 2007. Selenomethionine Biotransformation and Incorporation into Proteins along a Simulated Terrestrial Food Chain. Environmental Science & Technology 41(10):3601-3606.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).