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Ferredoxins (from Latin ''ferrum'': iron + redox, often abbreviated "fd") are iron-sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co. and applied to the "iron protein" first purified in 1962 by Mortenson, Valentine, and Carnahan from the anaerobic bacterium ''Clostridium pasteurianum''. Another redox protein, isolated from spinach chloroplasts by Tagawa and Arnon in 1962, was termed "chloroplast ferredoxin". The chloroplast ferredoxin is involved in both cyclic and non-cyclic photophosphorylation reactions of photosynthesis. In non-cyclic photophosphorylation, ferredoxin is the last electron acceptor and reduces the enzyme NADP+ reductase. It accepts electrons produced from sunlight-excited chlorophyll and transfers them to the enzyme ferredoxin:NADP+ oxidoreductase . Ferredoxins are small proteins containing iron and sulfur atoms organized as iron-sulfur clusters. These biological "capacitors" can accept or discharge electrons, the effect being change in the oxidation states (+2 or +3) of the iron atoms. This way, ferredoxin acts as electron transfer agents in biological redox reactions. Other bioinorganic electron transport systems include rubredoxins, cytochromes, blue copper proteins, and the structurally related Rieske proteins. Ferredoxins can be classified according to the nature of their iron-sulfur clusters and by sequence similarity. == Fe2S2 ferredoxins == Members of the 2Fe-2S ferredoxin family have a general core structure consisting of beta(2)-alpha-beta(2), which includes putidaredoxin and terpredoxin, and adrenodoxin. They are proteins of around one hundred amino acids with four conserved cysteine residues to which the 2Fe-2S cluster is ligated. This conserved region is also found as a domain in various metabolic enzymes and in multidomain proteins, such as aldehyde oxidoreductase (N-terminal), xanthine oxidase (N-terminal), phthalate dioxygenase reductase (C-terminal), succinate dehydrogenase iron-sulphur protein (N-terminal), and methane monooxygenase reductase (N-terminal). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ferredoxin」の詳細全文を読む スポンサード リンク
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