Send to

Choose Destination
See comment in PubMed Commons below
DNA Cell Biol. 2002 Apr;21(4):251-7.

HO2*: the forgotten radical.

Author information

Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.


HO2*, usually termed either hydroperoxyl radical or perhydroxyl radical, is the protonated form of superoxide; the protonation/deprotonation equilibrium exhibits a pK(a) 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 "perhydroxyl" in their titles, as against 9228 mentioning superoxide. Here it is argued that this correlation is not justifiable: that HO2*'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 HO2* is postulated. It is suggested that a more widespread appreciation of the possible role of HO2* in biological systems would be of considerable benefit to biomedical research.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Mary Ann Liebert, Inc.
    Loading ...
    Support Center