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Updated: Jan 29, 2026
11:05
Analysis of Oxidative Stress in Zebrafish Embryos
Published on: July 7, 2014
38.2K
Evolutionary adaptations that enable enzymes to tolerate oxidative stress
James A Imlay1, Ramakrishnan Sethu1, Sanjay Kumar Rohaun1
1Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA.
Free Radical Biology & Medicine
|February 9, 2019
Summary
Early life
Area of Science:
- Biochemistry
- Evolutionary Biology
- Molecular Biology
Background:
- Metabolic pathways evolved before atmospheric oxygen.
- Rising oxygen levels posed a threat to radical-based and iron-dependent enzymes.
- Enzymes using these mechanisms persist in modern organisms, both in anoxic and oxic environments.
Purpose of the Study:
- To review protein adaptations enabling radical and iron chemistry in oxygen-rich environments.
- To highlight how enzymes overcome oxygen toxicity.
- To emphasize the role of structural modifications in enzyme survival.
Main Methods:
- Literature review of protein adaptations.
- Analysis of structural modifications in enzymes.
- Survey of biochemical mechanisms in oxic and anoxic environments.
Main Results:
- Accessory domains shield vulnerable enzyme centers from oxygen.
- Iron cofactors evolved to less oxidizable forms or were replaced by alternative metals.
- Enzymes adapted through structural modification to function in aerobic conditions.
Conclusions:
- Some biochemical mechanisms are fundamentally incompatible with oxygen.
- Structural modifications are crucial for enzymes to function in oxic environments.
- Protein adaptations are an under-recognized solution to oxygen-induced enzyme inactivation.
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