Interaction kinetics of selenium-containing compounds with oxidants

Luke Carroll; Kelly Gardiner; Marta Ignasiak; Jeppe Holmehave; Shingo Shimodaira; Thomas Breitenbach; Michio Iwaoka; Peter R Ogilby; David I Pattison; Michael J Davies

doi:10.1016/j.freeradbiomed.2020.05.007

Interaction kinetics of selenium-containing compounds with oxidants

Free Radic Biol Med. 2020 Aug 1:155:58-68. doi: 10.1016/j.freeradbiomed.2020.05.007. Epub 2020 May 19.

Authors

Affiliations

¹ Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark.
² Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia.
³ Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; Department of Chemistry, Adam Mickiewicz University, Poznan, Poland.
⁴ Department of Chemistry, Aarhus University, Aarhus, Denmark.
⁵ Brain Korea (BK21), Dept. of Chemistry, KAIST 373-1, Daejeon, South Korea.
⁶ Department of Chemistry, Tokai University, Hiratsuka, Japan.
⁷ The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia; Department of Plant and Environmental Sciences, University of Copenhagen, Denmark.
⁸ Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia. Electronic address: davies@sund.ku.dk.

PMID: 32439383
DOI: 10.1016/j.freeradbiomed.2020.05.007

Abstract

Selenium compounds have been identified as potential oxidant scavengers for biological applications due to the nucleophilicity of Se, and the ease of oxidation of the selenium centre. Previous studies have reported apparent second order rate constants for a number of oxidants (e.g. HOCl, ONOOH) with some selenium species, but these data are limited. Here we provide apparent second order rate constants for reaction of selenols (RSeH), selenides (RSeR') and diselenides (RSeSeR') with biologically-relevant oxidants (HOCl, H₂O₂, other peroxides) as well as overall consumption data for the excited state species singlet oxygen (¹O₂). Selenols show very high reactivity with HOCl and ¹O₂, with rate constants > 10⁸ M^-1 s^-1, whilst selenides and diselenides typically react with rate constants one- (selenides) or two- (diselenides) orders of magnitude slower. Rate constants for reaction of diselenides with H₂O₂ and other hydroperoxides are much slower, with k for H₂O₂ being <1 M^-1 s^-1, and for amino acid and peptide hydroperoxides ~10² M^-1 s^-1. The rate constants determined for HOCl and ¹O₂ with these selenium species are greater than, or similar to, rate constants for amino acid side chains on proteins, including the corresponding sulfur-centered species (Cys and Met), suggesting that selenium containing compounds may be effective oxidant scavengers. Some of these reactions may be catalytic in nature due to ready recycling of the oxidized selenium species. These data may aid the development of highly efficacious, and catalytic, oxidant scavengers.

Keywords: Antioxidant; Hypochlorous acid; Oxidation; Photooxidation; Scavenger; Selenium; Singlet oxygen.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Hydrogen Peroxide
Hypochlorous Acid
Kinetics
Oxidants
Oxidation-Reduction
Selenium Compounds*
Selenium*

Substances

Oxidants
Selenium Compounds
Hypochlorous Acid
Hydrogen Peroxide
Selenium