Electrochemistry of Iron-Sulfur Proteins

Iron-sulfur proteins are non-heme electron carriers present in a wide range of living organisms and are known to cover different and important roles in biological processes. They will be treated here in order of their increasing iron content. 

One obviously expects that these Fe(III) compounds exhibit a Fe(III)/ Fe(II) reduction. However, since the protein has a total negative charge of-13 at pH 7 (pi 3), a situation which is electrostatically opposite to that of cytochrome c, it is fairly intuitive that the use of a perpendicularly 

Similar well-shaped responses have been obtained at a gold electrode using the aminoglycoside neomycin (neomycin sulfate), which is a positively charged promoter favouring the electrostatic interaction with negatively charged proteins.36 

These proteins (FW 11 000) bear a strongly negative charge (-18 in the oxidised state -19 in the reduced state). It is therefore expected that treating a perpendicular pyrolytic graphite electrode with positive additives will afford good results. In effect, under those conditions 

Concerning the 2Fe ferredoxins, the reduction process [2Fe-2S]2 + /+, which corresponds to the redox change  

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Armstrong, F.A. (1992) Dynamic electrochemistry of iron-sulfur proteins. Advances in Inorganic Chemistry, 38, 117-163. 

Redox catalysis is the catalysis of redox reactions and constitutes a broad area of chemistry embracing biochemistry (cytochromes, iron-sulfur proteins, copper proteins, flavodoxins and quinones), photochemical processes (energy conversion), electrochemistry (modified electrodes, organic synthesis) and chemical processes (Wacker-type reactions). It has been reviewed altogether relatively recently [2]. We will essentially review here the redox catalysis by electron reservoir complexes and give a few examples of the use of ferrocenium derivatives. 

Spectroelectrochemistry as a combination of electrochemistry and UVA IS spectroscopy is self-evident because of the direct relation of electron transfer with changes in electronic orbitals and thus with spectral changes. In redox proteins, with a few exceptions, the redox activity is caused by cofactors such as hemes, quinines, iron sulfur centers or metal centers, depending on the function and on the potential range. The role of the protein backbone and the amino acid side chains is the binding and precise orientation of these cofactors and the fine-tuning of their optical and redox properties with polarity or charges. In this context, the protein must able to react to redox transitions with conformational... 

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