Nauser, ThomasKoppenol, Willem H.Schoeneich, Christian2017-03-092017-03-092016-11-22Nauser, Thomas, Willem H. Koppenol, and Christian Schöneich. "Protein Thiyl Radical Reactions and Product Formation: A Kinetic Simulation." Free Radical Biology and Medicine 80 (2015): 158-63.https://hdl.handle.net/1808/23394Protein thiyl radicals are important intermediates generated in redox processes of thiols and disulfides. Thiyl radicals efficiently react with glutathione and ascorbate, and the common notion is that these reactions serve to eliminate thiyl radicals before they can enter potentially hazardous processes. However, over the past years increasing evidence has been provided for rather efficient intramolecular hydrogen transfer processes of thiyl radicals in proteins and peptides. Based on rate constants published for these processes, we have performed kinetic simulations of protein thiyl radical reactivity. Our simulations suggest that protein thiyl radicals enter intramolecular hydrogen transfer reactions to a significant extent even under physiologic conditions, i.e. in the presence of 30 μM oxygen, 1 mM ascorbate and 10 mM glutathione. At lower concentrations of ascorbate and glutathione, frequently observed when tissue is exposed to oxidative stress, the extent of irreversible protein thiyl radical-dependent protein modification increases.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License 3.0 (CC BY-NC-ND 3.0 US), which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.http://creativecommons.org/licenses/by-nc-nd/3.0/Thiyl radicalsHydrogen atom transferCarbon-centered radicalsD-amino acidsGlutathioneArticle10.1016/j.freeradbiomed.2014.12.006openAccess