HO2•: The Forgotten Radical

Aubrey D.N.J. de Grey
2002 DNA and Cell Biology  
HO 2 •, usually termed either hydroperoxyl radical or perhydroxyl radical, is the protonated form of superoxide; the protonation/deprotonation equilibrium exhibits a pKa of around 4.8. Consequently, about 0.3% of any superoxide present in the cytosol of a typical cell is in the protonated form. This ratio is rather accurately reflected by the published literature on the two species, as identified by a PubMed search; at the time of writing only 28 articles mention "HO2", "hydroperoxyl" or
more » ... operoxyl" or "perhydroxyl" in their titles, as against 9228 mentioning superoxide. Here it is argued that this correlation is not justifiable: that HO 2 •'s biological and biomedical importance far exceeds the attention it has received. Several key observations of recent years are reviewed that can be explained much more economically when the participation of HO 2 • is postulated. It is suggested that a more widespread appreciation of the possible role of HO 2 • in biological systems would be of considerable benefit to biomedical research. de Grey
doi:10.1089/104454902753759672 pmid:12042065 fatcat:7o7a3yk7jbc2hcx3yet2yu3tae