Chemical transformations redox behavior

Hydrophobic character of carbon pastes Consensually, it is the most typical feature of traditional carbon pastes due to the lipophilic nature of both paraffin and silicone oils forming the electrode material [2,4,5,8-10,35,36, 50]. The principal consequence of such hydrophobicity is moderated reaction kinetics at carbon paste-based electrodes [2,5,7,50], reflected in more or less irreversible behavior of numerous inorganic redox pairs and organic systems involved in chemical transformations at the electrode surface. (The reason for such behavior is mainly a repelling effect between the hydrophobic surface of CPEs and typically hydrophilic character of the compounds participating in the individual reactions [2, 5,7-10,16, 50].)... 

This particular reaction has been chosen for the reason of its high value of standard chemical affinity for this reaction (j / = — 7.1 kcal/mole). As we noted above, due to this circumstance the system behavior can reveal the deviation from that prescribed by the classical Arrhenius mechanism. The conformational changes in malatdehydrogenase were tested by measuring the average life-time of intrinsic tryptophane fluorescence (ff). This parameter is known to be sensitive to the immediate surrounding of tryptophane residues. The chemical transformation of the substrate was detected from changes in the coenzyme redox state measured in terms of the sample optical density at 340 nm (NADH absorption maximum). 

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