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Updated: Aug 6, 2026
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Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Oligomer-dependent heme-binding to human peroxiredoxin 1
Takeshi Uchida1, Hiroto Osawa2, Koichiro Ishimori1
1Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan; Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-8628, Japan.
International Journal of Biological Macromolecules
|July 25, 2026
Summary
Decameric peroxiredoxin 1 (PRX1) binds heme, enhancing its peroxidase activity and stability. This interaction protects heme from degradation and regulates antioxidant function.
Area of Science:
- Biochemistry
- Enzymology
- Oxidative Stress
Background:
- Peroxiredoxin 1 (PRX1) is a thiol-based peroxidase active against hydrogen peroxide.
- PRX1 exists in monomeric, dimeric, and decameric forms, with the decamer being most abundant and active.
- Previous work showed monomeric PRX1 loses activity upon heme binding via Cys52.
Purpose of the Study:
- Investigate heme binding effects on the decameric form of human PRX1.
- Determine the impact of heme on decameric PRX1's activity, stability, and oligomeric state.
Main Methods:
- Spectroscopic titration to analyze heme binding kinetics.
- UV-vis spectroscopy to characterize heme coordination.
- Enzyme activity assays to measure peroxidase function.
- Analysis of oligomeric state under varying conditions.
Main Results:
- Decameric PRX1 binds one heme per subunit with a dissociation constant of 2.3 ± 1.9 μM.
- Heme binding to decameric PRX1 enhances peroxidase activity ~2-fold.
- Heme binding protects PRX1-bound heme from H2O2-induced degradation.
- Heme binding promotes the decameric form under oxidizing conditions.
Conclusions:
- Decameric PRX1 binds heme through histidine coordination, unlike the monomeric form.
- Heme binding to decameric PRX1 enhances antioxidant capacity and stability.
- Decameric PRX1 acts as a heme scavenger and regulator of antioxidant activity.
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