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Was hydrogen peroxide present before the arrival of oxygenic photosynthesis? The important role of iron(II) in the Archean ocean.

Was hydrogen peroxide present before the arrival of oxygenic photosynthesis? The important role of iron(II) in the Archean ocean.

Authors :
Koppenol WH
Sies H
Source :
Redox biology [Redox Biol] 2024 Feb; Vol. 69, pp. 103012. Date of Electronic Publication: 2023 Dec 25.
Publication Year :
2024

Abstract

We address the chemical/biological history of H <subscript>2</subscript> O <subscript>2</subscript> back at the times of the Archean eon (2.5-3.9 billion years ago (Gya)). During the Archean eon the pO <subscript>2</subscript> was million-fold lower than the present pO <subscript>2</subscript> , starting to increase gradually from 2.3 until 0.6 Gya, when it reached ca. 0.2 bar. The observation that some anaerobic organisms can defend themselves against O <subscript>2</subscript> has led to the view that early organisms could do the same before oxygenic photosynthesis had developed at about 3 Gya. This would require the anaerobic generation of H <subscript>2</subscript> O <subscript>2</subscript> , and here we examine the various mechanisms which were suggested in the literature for this. Given the concentration of Fe <superscript>2+</superscript> at 20-200 μM in the Archean ocean, the estimated half-life of H <subscript>2</subscript> O <subscript>2</subscript> is ca. 0.7 s. The oceanic H <subscript>2</subscript> O <subscript>2</subscript> concentration was practically zero. We conclude that early organisms were not exposed to H <subscript>2</subscript> O <subscript>2</subscript> before the arrival of oxygenic photosynthesis.<br />Competing Interests: Declaration of competing interest There is no conflict of interest.<br /> (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
2213-2317
Volume :
69
Database :
MEDLINE
Journal :
Redox biology
Publication Type :
Academic Journal
Accession number :
38183797
Full Text :
https://doi.org/10.1016/j.redox.2023.103012