Is Hydrogen Peroxide Produced during Iron(II) Oxidation in Mammalian Apoferritins?

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• 作者：Guanghua Zhao ; Fadi Bou-Abdallah ; Xiaoke Yang ; Paolo Arosio ; and N. Dennis Chasteen
• 刊名：Biochemistry
• 出版年：2001
• 出版时间：September 11, 2001
• 年：2001
• 卷：40
• 期：36
• 页码：10832 - 10838
• 全文大小：85K
• 年卷期：v.40,no.36(September 11, 2001)
• ISSN：1520-4995

文摘

The ferritins are a class of iron storage and detoxification proteins that play a central role inthe biological management of iron. These proteins have a catalytic site, "the ferroxidase site", located onthe H-type subunit that facilitates the oxidation of Fe(II) to Fe(III) by O₂. Measurements during the past10 years on a number of vertebrate ferritins have provided evidence that H₂O₂ is produced at this diironferroxidase site. Recently reported experiments using three different analytical methods with horse spleenferritin (HoSF) have failed to detect H₂O₂ production in this protein [Lindsay, S., Brosnahan, D., andWatt, G. D. (2001) Biochemistry 40, 3340-3347]. These findings contrast with earlier results reportingH₂O₂ production in HoSF [Xu, B., and Chasteen, N. D. (1991) J. Biol. Chem. 266, 19965-19970]. Herea sensitive fluorescence assay and an assay based on O₂ evolution in the presence of catalase were usedto demonstrate that H₂O₂ is produced in HoSF as previously reported. However, because of the relativelyfew H-chain ferroxidase sites in HoSF and the reaction of H₂O₂ with the protein, H₂O₂ is more difficultto detect in this ferritin than in recombinant human H-chain ferritin (HuHF). The proper sequence ofaddition of reagents is important for measurement of the total amount of H₂O₂ produced during theferroxidation reaction.