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Abiotic sulfhydryl reactivity: a predictor of aquatic toxicity for carbonyl-containing alpha,beta-unsaturated compounds
Chemical research in toxicology (2007)
  • J W Yarbrough
  • Terry W Schultz, University of Tennessee - Knoxville
Abstract

A diverse series of aliphatic alpha,beta-unsaturated esters, ketones, and aldehydes were evaluated for reactivity with the model nucleophile sulfhydryl group in the form of the cysteine residue of the tripeptide glutathione; the reactive end point (RC50) was then related to aquatic toxicity (IGC50) assessed in the Tetrahymena pyriformis population growth impairment assay. The substructure specific to all tested reactive substances, an olefin conjugated to a carbonyl group, is inherently electrophilic and conveys the potential to act by way of Michael-type nucleophilic addition. All such unsaturated compounds are inherently acutely toxic. However, their toxicity is difficult to model with conventional descriptors since toxicity is independent of both hydrophobicity and molecular orbital electrophilicity but dependent on the specific molecular structure. While methacrylates typically did not attain an RC50 value at saturation, a linear relationship [log (IGC50(-1)) = 0.936[log (RC50(-1))] + 0.508, where n = 41, r2 = 0.846, q2 = 0.832, s = 0.35, F = 214, and Pr > F = 0.0001] was observed between aquatic toxicity and reactivity for the other carbonyl-containing alpha,beta-unsaturated chemicals.

Publication Date
2007
Citation Information
J W Yarbrough and Terry W Schultz. "Abiotic sulfhydryl reactivity: a predictor of aquatic toxicity for carbonyl-containing alpha,beta-unsaturated compounds" Chemical research in toxicology Vol. 20 Iss. 3 (2007)
Available at: http://works.bepress.com/terry_schultz/17/