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Protein binding in deactivation of ferrylmyoglobin by chlorogenate and ascorbate
C U Carlsen1, M V Kröger-Ohlsen, R Bellio
1Food Chemistry, Department of Dairy and Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
Journal of Agricultural and Food Chemistry
|February 26, 2000
Summary
This study reveals chlorogenate effectively reduces ferrylmyoglobin, a key step in antioxidant activity. The findings detail reaction kinetics and highlight a novel antioxidant interaction involving chlorogenate and ferrylmyoglobin.
Area of Science:
- Biochemistry and Biophysics
- Chemical Kinetics
- Oxidative Stress Research
Background:
- Ferrylmyoglobin (Fm) is a reactive intermediate implicated in oxidative damage.
- Understanding its reduction kinetics is crucial for developing antioxidant strategies.
- Chlorogenate is a plant-derived polyphenol with potential antioxidant properties.
Purpose of the Study:
- To investigate the kinetics of ferrylmyoglobin reduction by chlorogenate.
- To elucidate the reaction mechanism, including protonation states of ferrylmyoglobin.
- To explore the antioxidant interaction between chlorogenate and ferrylmyoglobin.
Main Methods:
- Stopped-flow absorption spectroscopy was employed to monitor reaction rates.
- Experiments were conducted in neutral to moderately acidic aqueous solutions.
- Kinetic data were analyzed to determine rate constants and thermodynamic parameters.
Main Results:
- Direct bimolecular electron transfer was observed for both protonated and non-protonated ferrylmyoglobin.
- Rate constants varied depending on the protonation state of ferrylmyoglobin.
- A chlorogenate-ferrylmyoglobin complex formation was identified, influencing the reduction pathway.
Conclusions:
- Chlorogenate effectively reduces ferrylmyoglobin, indicating a significant antioxidant capacity.
- The binding of chlorogenate modulates ferrylmyoglobin's reactivity, leading to a novel antioxidant interaction.
- Re-evaluation of existing data suggests similar mechanisms apply to other reductants like ascorbate.