Catalases (CAT) are antioxidant metalloenzymes necessary for life in oxygen-metabolizing cells to regulate H2O2 concentration by accelerating its dismutation. Many physiopathological situations associated with oxidative stress resulting from overproduction, during which defenses overwhelmed. We have used a combinatorial approach an activity-based screening discover first peptidyl di-copper comp...

Endowing anti-fouling capabilities to water treatment membranes is a key feature for their long lifetime, but it continues be challenging task. Herein, strategy preparing composite reported comprising halloysite nanotubes (HNTs) as scaffolds support ruthenium substituted polyoxometalate (Ru4POM), with the goal of using evolved O2, resulting from Ru4POM-catalyzed H2O2 dismutation, agent. Two dif...

complex reacted rapidly with 02-. in a catalytic manner. The rate constant for O,-* dismutation was determined by competition of the iron porphyrin with Nitro Blue Tetrazolium in a xanthine/xanthine oxidase system at pH 10.1 ; a value of 3 x ~O'M-' .s-' at 20°C was obtained. The iron porphyrin had no effect on xanthine oxidase activity. Under our reaction conditions, at least 14 molecules of Oz...

The Cu,ZnSODs (Cu,Zn superoxide dismutases) comprise a class of ubiquitous metalloenzymes that catalyse the dismutation of the superoxide radical anion into oxygen and hydrogen peroxide. The dismutation reaction involves two successive encounters of the superoxide anion with a catalytic copper centre hosted by the enzyme at the dead end of a narrow protein channel. Cu,ZnSOD is found in all euka...

Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo-ket...

The results obtained led the authors to the suggestion that Reactions 2 and 4 are catalyzed by liver alcohol dehydrogenase but that Reaction 1 is due to an aldehyde dehydrogenase present in their liver preparation. Because of the inhomogeneity of the enzyme preparation employed, a reinvestigation of this problem with more highly purified enzyme was suggested. With the use of crystalline horse l...

Hangman Fe(III) corroles catalyse H(2)O(2) disproportionation at a faster rate and display a more pronounced hangman effect than their one electron oxidized analogues owing to their ability to bypass high energy intermediates by redox-leveling derived from the use of the corrole as a non-innocent ligand.

Superoxide (O2 ) is the compound obtained when oxygen is reduced by one electron. For a molecule with an unpaired electron, O2 is surprisingly inert, its chief reaction being a dismutation in which it reacts with itself to form H2O2 and oxygen. The involvement of O2 in biological systems was first revealed by the discovery in 1969 of superoxide dismutase, an enzyme that catalyzes the dismutatio...

A carbon nanotube-gold nanohybrid was used as catalyst for the reduction of molecular oxygen in acidic and alkaline media, the relevant cathode reaction in fuel cells. In alkaline medium, the nanohybrid exhibits excellent activity with a dominant 4e(-) reduction of O2 and low overpotential requirement compared to previously reported nano-gold materials. This property is linked to its capability...

Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo-ket...