Oxidation active sites

Trofanchuk, O., Stein, M., Gessner, C., Lendzian, E, Higuchi, Y. and Lubitz, W. (2000) Single crystal EPR studies of the oxidized active site of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F. J. Biol. Inorg. Chem., 5, 364-4. 

Figure 16. Consensus oxidized active-site structures of the xanthine oxidase (XO), sulfite oxidase (SO), and DMSO reductase (DMSOR), and aldehyde oxidoreductase (AOR) families of mononuclear molybdenum and tungsten enzymes and the structure of the common ppd cofactor (41, 42). The question mark in the AOR structure indicates uncertainty in the presence of a coordinated water molecule.

Method of EPR-tomography developed in the Institute of Chemical Physics of RAS [46] allows both detecting of molecular mobility and its change at thermo- or photo-destruction of polymer in various points of sample and registration of the distribution of oxidation active sites through the sample. This method allows identification of polymers parts in which destruction process proceeds. Solution of this problem is of great importance for selection of conditions of polymer materials exploitation. 

Figure 1 Classification of Mo-MPT enzymes. Structures (l)-(3) represent oxidized active-site structures (only the dithiolene moiety of each MPT-based ligand is shown)...

The structure of another member of this family, the selenocysteine-containing formate dehydrogenase H from E. coli, has also been determined it contains an [Mo 0(SeCys)(MGD)2] oxidized active site see Selenium Proteins Containing Selenocysteine). Formate dehydrogenases catalyze the interconversion of formate and carbon dioxide and play an important role in global fixation of carbon dioxide. ... 

Sorokin AB, Quignard F, Valentin R, Mangematin S (2006) Chitosan supported phthalo-cyanine complexes Bifunctional catalysts with basic and oxidation active sites. Appl Cat A 309 162... 

Molybdenum and tungsten complexes as models for oxygen atom transfer enzymes have been deployed in the full catalytic cycle from Scheme 4.3 predominantly in the early days of this field of research. A selection of the respective determined Michaelis-Menten parameters were expertly reviewed by Holm et al. Since in some cases both forms of model complexes (M and M mimicking the fully reduced or fully oxidized active sites, respectively) are isolable and available in a sufficient amount, the isolated half-reactions are much more often investigated than the whole catalytic cycle. This means that either the reduced form of the enzyme model is oxidized by an oxygen donor substrate like TMAO or the oxidized form is reduced by an oxygen acceptor substrate like triphenylphosphine (PhgP). The observed kinetic behaviour is in some cases described to be of a saturation type. An observation which... 

The biological studies summarized above have fully defined the oxidized active sites of the enzymes and provided idealized targets for MoHM studies. These targets are represented in structures (l)-(4), in rough order of prevalence in enzymes. In the enzymes, the dithiolene ligand represents MPT (or a dinucleotide derivative thereof) while in models it represents a synthetic simulant of this unique biological ligand. 

Although structurally related to the Mo hydroxylases, the active structure of the molybdenum containing CODH enzyme is unique among pyranopterin Mo enzymes in that it possesses a heterobimetallic Mo/Cu active site. " In the oxidized resting state, the Mo ion is in the Mo(vi) state while the Cu is reduced in the Cu(i) state. This is interesting since this leads to an oxidized active site that possesses metal centers that differ by five units in oxidation state and by ten d-electrons. However, only the Mo ion is believed to be redox active in the catalytic sequence. The Mo and Cu ions are covalently... 

Sorokin, A., Quignard, R, Valentin, R., et al. (2006). Chitosan Supported Phthalocyanine Complexes Bifunctional Catalysts with Basic and Oxidation Active Sites, Ap/ Z. Cat. A., 309,... 

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