Carbon monoxide dehydrogenase mechanism

Barondeau, D. P., and Lindahl, P. A., 1997, Methylation of carbon monoxide dehydrogenase from Clostridium thermoaceticum and mechanism of acetyl coenzyme A synthesis, J. Am. Chem. Soc. 119(17) 3959n3970. 

Seravalli, J., Kumar, M., Lu, W.-P., and Ragsdale, S. W., 1997, Mechanism of carbon monoxide oxidation by the carbon monoxide dehydrogenase/acetyl-CoA syndiase from Clostridium thermoaceticum Kinetic characterization of the intermediates, Biochem. 36 11241fi 11251. 

Several important homogeneous catalytic reactions (e.g. hydroformylations) have been accomplished in water by use of water-soluble catalysts in some instances water can act as a solvent and as a reactant for hydroformylation. In addition, formation of aluminoxanes by partial hydrolysis of alkylaluminum halides results in very high activity bimetallic Al/Ti or Al/Zr metallocene catalysts for ethene polymerization which would be otherwise inactive. Polymerization of aryl diiodides and acetylene gas has recently been achieved in water with palladium catalysts. Finally, nickel-containing enzymes, such as carbon monoxide dehydrogenase (CODH) and acetyl-CoA synthase, operate in water with reaction mechanisms comparable with those of the WGSR or of the Monsanto methanol-to-acetic-acid process. ... 

In this chapter, we survey recent efforts to produce biologically inspired catalysts for proton and CO2 reduction. First, we introduce the biological catalysts that underpin this research hydrogenases, carbon monoxide dehydrogenases, and formate dehydrogenases. Then, we describe some of the most catalytically successful synthetic molecules that have been inspired by these biological catalysts, paying particular attention to catalytic properties and mechanism. 

Volbeda A, Fontecilla-Camps JC (2005) Structural bases for the catalytic mechanism of Ni-containing carbon monoxide dehydrogenases. Dalton Trans 3443-3450... 

Fig. 5. Proposed mechanism of ATP synthesis coupled to methyl-coenzyme M (CH3-S-C0M) reduction to CH4 The reduction of the heterodisulfide (CoM-S-S-HTP) as a site for primary translocation. ATP is synthesized via membrane-bound -translocating ATP synthase. CoM-S-S-HTP, heterodisulfide of coenzyme M (H-S-CoM) and 7-mercaptoheptanoylthreonine phosphate (H-S-HTP) numbers in circles, membrane-associated enzymes (1) CH3-S-C0M reductase (2) dehydrogenase (3) heterodisulfide reductase 2[H] can be either H2, reduced coenzymeF420 F420H2) or carbon monoxide the hatched box indicates an electron transport chain catalyzing primary translocation the stoichiometry of translocation (2H /2e , determined in everted vesicles) was taken from ref. [117] z is the unknown If /ATP stoichiometry A/iH, transmembrane electrochemical...

Oxidases catalyse oxidations in presence of free oxygen. Unlike the dehydrogenases, they are unable to use methylene blue, cytochrome or similar hydrogen acceptors, and they also differ in their sensitivity to inhibitors. Thus, urethane and related narcotics have no action on oxidases, but cyanide, carbon monoxide or hydrogen sulphide in concentrations as low as 0-01 M to O OOl M inhibit them completely. This is ascribed to the fixation of an active metallic radicle, usually Fe, in the oxidase effector mechanism. 

---