Dehydrogenase, carbon monoxide formate

Carbon monoxide oxidase, nicotinic acid hydroxylase, formate dehydrogenase and other 662... 

Conceptually, the simplest way to synthesize an organic molecule is to construct it one carbon at a time (Ragsdale and Pierce, 2008). The Woods—Ljungdahl pathway (Figure 15.3) does just that, synthesising acetyl-CoA from CO2. Carbon monoxide dehydrogenase, CODH and acetyl-CoA synthase, ACS are responsible for the reduction of CO2 to CO and the subsequent formation of acetyl-CoA (Drennan et al., 2004). CODH/ACS... 

For example, incorporation of nickel into carbon monoxide dehydrogenase of Rhodospirillum rubrum requires the prior reduction of an Fe-S cluster. Structural studies of this protein reveal that the added Ni completes a unique [lNi-4Fe-4S] center that is required for activity.Another example of a reductive activation step occurs during NiFe-hydrogenase biosynthesis, perhaps involving participation of the Fe-S cluster in HypD. Yet a third example from the Ni-enzyme literature involves the synthesis of methyl-X-coenzyme M reductase, a methanogen enzyme that contains the Ni-tetrapyrrole cofactor F43q. Formation of active enzyme requires both the reduction of Ni + to NF+ and reduction of a C=N bond in the organic macrocycle. 

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. ... 

Keywords Bio-inspired metallocomplexes Biomimicry Carbon monoxide dehydrogenase Catalysis Energy Formate dehydrogenase Hydrogenase... 

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. 

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