Ferric iron reduction

There is some evidence that the iron-sulfur protein, FhuF, participates in the mobilization of iron from hydroxamate siderophores in E. coli (Muller et ah, 1998 Hantke, K. unpublished observations). However, a reductase activity of FhuF has not been demonstrated. Many siderophore-iron reductases have been shown to be active in vitro and some have been purified. The characterization of these reductases has revealed them to be flavin reductases which obtain the electrons for flavin reduction from NAD(P)H, and whose main functions are in areas other than reduction of ferric iron (e.g. flavin reductase Fre, sulfite reductase). To date, no specialized siderophore-iron reductases have been identified. It has been suggested that the reduced flavins from flavin oxidoreductases are the electron donors for ferric iron reduction (Fontecave et ah, 1994). Recently it has been shown, after a fruitless search for a reducing enzyme, that reduction of Co3+ in cobalamin is achieved by reduced flavin. Also in this case it was suggested that cobalamins and corrinoids are reduced in vivo by flavins which may be generated by the flavin... 

Lovely D. R. and Phillips E. J. P. (1987) Competitive mechanisms for inhibition of sulfate reduction and methane production in the zone of ferric iron reduction in sediments. Appl. Environ. Microbiol. 53(11), 2636-2641. 

Brock, T.D., 1977. Ferric iron reduction by sulfur- and iron-oxidizing bacteria. Conference Bacterial Leaching. GBF Monograph Series, No. 4 (August 1977), p. 47. 

King, G. M., and Garey, M. A. (1999). Ferric iron reduction by bacteria associated with the roots of freshwater and marine macrophytes. Appl. Environ. Microbiology. 65, 4393-4398. 

Figure 26. Mechanisms of synthe.sis of thioesters. I) High temperature, low pH spontaneous synthesis from thiols and ornic acids (2) oxidative synthesis from thiols and a-keto organic acids based on ferric iron reduction (de Duve, 1995).

Shinkyo R, Guengerich FP (2011) Cytochrome P450 7A1 cholesterol 7alpha-hydroxylation individual reaction steps in the catalytic cycle and rate-limiting ferric iron reduction. J Biol Chem 286 4632 643... 

De Wilde, V., Rozendal, R.A., and Buisman, C.J.N. (2006) A bipolar membrane combined with ferric iron reduction as an efficient cathode system in microbial fuel cells. Environ. 

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