Dioxygen, activation

The hydroxylase enzyme of sMMO, with its non-heme diiron center, employs a dioxygen-activation pathway having some features in common with that proposed for cytochrome P450. Although full details of the mechanism remain to be estab- 

Recent kinetic data from single turnover experiments support the existence of an additional intermediate between H d and Q [59], possibly related to 14 or 15. 

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Volume 66 Dioxygen Activation and Homogeneous Catalytic Oxidation. Proceedings of the Fourth International Symposium on Dioxygen Activation and Homogeneous Catalytic Oxidation, Balatonfiired, September 10-14,1990 edited by L.l. Simandi... 

N-Heterocycles as ligands in dioxygen activation by enzymes containing binuclear nonheme iron clusters 96CRV2625. 

Scheme 10.25 Dioxygen activation in cofactor-free enzymes.

Dioxygen activation in transition metal complexes in the light of molecular orbital calculations. R. Boca, Coord. Chem. Rev., 1983, 50,1-72 (245). 

Volume 66 Dioxygen Activation and Homogeneous Catalytic Oxidation. Proceedings of the... 

Under conditions of copper deficiency, some methanotrophs can express a cytosolic, soluble form of MMO (sMMO) (20-23), the properties of which form the focus of the present review. The sMMO system comprises three separate protein components which have all been purified to homogeneity (24,25). The hydroxylase component, a 251 kD protein, contains two copies each of three subunits in an a 82y2 configuration. The a subunit of the hydroxylase houses the dinuclear iron center (26) responsible for dioxygen activation and for substrate hydroxylation (27). The 38.6 kD reductase contains flavin adenine dinucleotide (FAD) and Fe2S2 cofactors (28), which enable it to relay electrons from reduced nicotinamide adenine dinucleotide (NADH) to the diiron center in the... 

A much smaller amount of work has been done with nickel complexes of dmt ligands since they are more difficult to crystallize. Some complexes have been assembled combining [Ni(dmf)2] with viologen-based cations for applications in electrical conductivity and dioxygen activation.10 3-1035... 

Costas, M., M. P. Mehn et al. (2004). Dioxygen activation at mononuclear nonheme iron active sites Enzymes, models, and intermediates. Chem. Rev. 104(2) 939-986. 

Que, L. and R. Y. N. Ho (1996). Dioxygen activation by enzymes with mononuclear non-heme iron active sites. Chem. Rev. 96(7) 2607-2624. 

Dioxygenases often have broad substrate specificity and require only a minimal characteristic structure for substrate recognition [310], Transition metal or an organic cofactor mediates dioxygen activation needed by the oxygenases action. Iron and copper, in their lower oxidation states are the metals most commonly used, but also organic co-factors like dihydroflavin and tetrahydropterin are able to activate the oxygen molecule. 

Dioxygen Activation by Transition Metal Complexes. Atom Transfer and Free Radical Chemistry in Aqueous Media... 

Koehntop, K.D., Emerson, J.P. and Que, L. Jr. (2005) The 2-His-l-carboxylate facial triad a versatile platform for dioxygen activation by mononuclear non-heme iron(II) enzymes, J. Biol. Inorg. Chem., 10, 87-93. 

Theopold KH (2007) Dioxygen Activation by Organometallics of Early Transition Metals. 22 17-37... 

The enzymes of this type that have been characterized contain some type of redox-active cofactor, such as a flavin (3), or a metal ion (heme iron, non-heme iron, or copper), or both (4-6). Our understanding of the mechanism of these enzymes is most advanced in the case of the heme-containing enzyme cytochrome P450. But in spite of the availability of a crystal structure of an enzyme-substrate complex (7) and extensive information about related reactions of low molecular weight synthetic analogues of cytochrome P450 (8), a detailed picture of the molecular events that are referred to as "dioxygen activation" continues to elude us. 

L. L. Simandi, Dioxygen Activation and Homogeneous Catalytic Oxidations, Elsevier, Amsterdam, 1991. 

James BR (1991) In Simdndi LI (ed) Dioxygen activation and homogeneous catalytic oxidation. Elsevier Science Publishers BV, Amsterdam, pp 195-212... 

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