A new ground-state organic electron donor has been prepared that features four strongly π-donating iminophosphorano substituents on a bispyridinylidene skeleton. Cyclic voltammetry reveals a record redox potential of -1.70 V vs. saturated calomel electrode (SCE) for the couple involving the neutral organic donor and its dication. This highly reducing organic compound can be isolated (44 %) or m...

Systematic studies based on 1H NMR and 13C NMR indicated that the alkylthio group behaves as a weak electron-withdrawing group in a simple aniline system like 2-butylthioaniline, while the same alkylthio group clearly acted as a resonance electron-donating group in higher conjugated aniline trimer systems, like butylthio-substituted PDA (mono-PDA) and dibutylthio-substituted PDA (2,6-diPDA). Th...

Rapidly fluctuating environmental conditions can significantly stress organisms, particularly when fluctuations cross thresholds of normal physiological tolerance. Redox potential fluctuations are common in humid tropical soils, and microbial community acclimation or avoidance strategies for survival will in turn shape microbial community diversity and biogeochemistry. To assess the extent to w...

The potential for branched-chain 2-oxo acid dehydrogenase complex (BCOADC) activity to be controlled by feedback inhibition was investigated by calculating the Elasticity Coefficients for several feedback inhibitors. We suggest that feedback inhibition is a quantitatively important regulatory mechanism by which branched-chain 2-oxo acid dehydrogenase activity is regulated. The potential for con...

Synthetic/artificial protein switches provide an efficient means of controlling protein functions using chemical signals and stimuli. Mutually exclusive proteins, in which only the host or guest domain can remain folded at a given time owing to conformational strain, have been used to engineer novel protein switches that can switch enzymatic functions on and off in response to ligand binding. T...

Cytochrome c was adsorbed readily and remained electroactive, with a redox potential of 32 mV, on TiO2 films placed on SnO2; similar behaviour was observed in glycerol, whereas in acetonitrile, irreversible oxidation occurred at a potential of 800 mV.

Oxidation (off state) and reduction (on state) of a single azurin molecule is monitored, one electron at a time, which depend on the chemical redox potential. By analysing the fluorescence time traces from individual azurin molecules, reaction kinetics and redox thermodynamics were determined.

The wide range of variability of the reduction potential (E(0)) of blue-copper proteins has been the subject of a large number of studies in the past several years. In particular, a series of azurin mutants have been recently rationally designed tuning E(0) over a very broad range (700 mV) without significantly altering the redox-active site [Marshall et al., Nature, 2009, 462, 113]. This clear...

It is no surprise that the catalytic activity of electron-transport enzymes may be optimised at certain electrochemical potentials in ways that are analogous to observations of pH-rate optima. This property is observed clearly in experiments in which an enzyme is adsorbed on an electrode surface which can supply or receive electrons rapidly and in a highly controlled manner. In such a way, the ...

The same non-covalent interactions previously found to affect the redox potential (E(m)) of the mononuclear T1 Cu protein azurin (Az) are shown to also fine-tune the E(m) of the dinuclear Cu(A) center in the same Az protein scaffold. The effects of these mutations are in the same direction but with smaller magnitude in the Cu(A) site, due to dissipation of the effects by the dinuclear Cu(A) cen...