Theoretical Study of the Reactivity and Selectivity of Various Free Radicals with Cysteine Residues.

ABSTRACT: Radicals in biochemical environments can lead to protein damage. Theoretical studies can help us to understand the observed radical selectivity. In this work, the kinetics and thermodynamics of the hydrogen-transfer (HT) and single-electron transfer (SET) reactions between a cysteine derivative and 17 free radicals of biological significance have been theoretically investigated in aqueous and lipid media. With the exception of the reaction with ^•OCCl₃, all SET reactions in aqueous medium have rate constants in the diffusion-limited regime. The γ site of cysteine was found to be the most reactive for the HT reactions with all the radicals, with rate constants in the diffusion limit for ^•OH, ^•OCHCl₂, and ^•OCCl₃. The

SUBMITTER: Romero-Silva A 

PROVIDER: S-EPMC6643617 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature