The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews examples in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many examples in which enzymes are interfaced with electronically conductive particles to build up heterogeneous cata...

We report an air electrode employing polyimide-coated carbon nanotubes (CNTs) combined with a redox mediator for Li-O2 cells with enhanced electrochemical performance. The polyimide coating on the carbon surface suppresses unwanted side reactions, which decreases the amount of accumulated reaction products on the surface of the air electrode during cycling. The redox mediators lower the overpot...

Bleaching of kaempferol by illuminated chloroplasts was observed at 380 nanometers. The photobleaching was stimulated by methyl viologen and suppressed by superoxide dismutase indicating the participation of O(2) (-) in the reaction. An electron transfer inhibitor on the oxidizing side of photosystem II, carbonylcyanide m-chlorophenylhydrazone (CCCP), stimulated the photobleaching and 3-(3,4-di...

Mitochondria have a myriad of essential functions including metabolism and apoptosis. These chief functions are reliant on electron transfer reactions and the production of ATP and reactive oxygen species (ROS). The production of ATP and ROS are intimately linked to the electron transport chain (ETC). Electrons from nutrients are passed through the ETC via a series of acceptor and donor molecul...

Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel ch...

The origin in rocks of the common iron sulphides, pyrrhotine, Fe 1 xS and pyrite, FeS2 and their behaviour during geochemical processes is best considered using the simplified redox reaction: 2FeS ~-~ FeS2 + Fe 2 + + 2e . Thus pyrrhotine is more reduced than pyrite and is the stable iron sulphide formed from magmas except where relatively high oxygen fugacities result from falling pressure or h...

Neutrophil granulocyte leukocytes (neutrophils) play fundamental role in the innate immune response. In the presence of adequate stimuli, neutrophils release excessive amount of reactive oxygen species (ROS) that may induce cell and tissue injury. Oxidative burst of neutrophils acts as a double-edged sword. It may contribute to the pathology of atherosclerosis and brain injury but is also neces...

Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalizat...

One-electron reduction significantly enhances the ability of anthralin, 1, to act as a hydrogen atom donor. On annealing of an MTHF glass in which the radical anion of anthralin, 1*-, is generated radiolytically, this species decays mainly by loss of H* to give the anthralyl anion, 2- . On the other hand, radicals formed on radiolysis of matrices that are suitable for the generation of radical ...

Spatial oscillations in soil contaminant concentration profiles are sometimes observed, but rarely commented on, or are attributed to noisy data. In this paper we consider a possible mechanism for the occurrence of oscillatory reactant profiles within contaminant plumes. The bioremediative reactions which occur are effected by bacteria, whose rôle is normally conceived of as being passive. Here...