Was H2O2 generated before oxygenic photosynthesis?
Willem H. Koppenol,
Helmut Sies
Affiliations
Willem H. Koppenol
Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Zürich, Switzerland; Corresponding author. Schwändibergstrasse 25, CH-8784, Braunwald, Switzerland.
Helmut Sies
Institute for Biochemistry and Molecular Biology I, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany; Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
We obviously agree with Wu et al. that H2O2 might accumulate in the Archean land waters devoid of Fe2+. We do disagree on the topic of the half-life of H2O2, as the work cited in support for a longer half-live is not relevant to the conditions in the Archean ocean. While the existence of radicals in quartz is not in doubt, we do question the hypothesis that these radicals oxidize water to HO• and H2O2.
