Enzyme methane monooxygenase

In some cases, microorganisms can transform a contaminant, but they are not able to use this compound as a source of energy or carbon. This biotransformation is often called co-metabolism. In co-metabolism, the transformation of the compound is an incidental reaction catalyzed by enzymes, which are involved in the normal microbial metabolism.33 A well-known example of co-metabolism is the degradation of (TCE) by methanotrophic bacteria, a group of bacteria that use methane as their source of carbon and energy. When metabolizing methane, methanotrophs produce the enzyme methane monooxygenase, which catalyzes the oxidation of TCE and other chlorinated aliphatics under aerobic conditions.34 In addition to methane, toluene and phenol have been used as primary substrates to stimulate the aerobic co-metabolism of chlorinated solvents. 

Non-heme Di-Iron Enzymes Methane Monooxygenase and Ribonucleotide Reductase... 

Metalloenzymes with non-heme di-iron centers in which the two irons are bridged by an oxide (or a hydroxide) and carboxylate ligands (glutamate or aspartate) constitute an important class of enzymes. Two of these enzymes, methane monooxygenase (MMO) and ribonucleotide reductase (RNR) have very similar di-iron active sites, located in the subunits MMOH and R2 respectively. Despite their structural similarity, these metal centers catalyze very different chemical reactions. We have studied the enzymatic mechanisms of these enzymes to understand what determines their catalytic activity [24, 25, 39-41]. 

The enzyme methane monooxygenase converts methane into methanol, producing water as a byproduct. 

What are the substrates used by the enzyme methane monooxygenase What products does this enzyme make ... 

The non-heme enzyme methane monooxygenase (MMO) from methanotropic bacteria catalyzes the hydroxylation of methane to methanol. Methane is most difficult to hydroxylate and cytochrome P-450 cannot perform this reaction. MMO consists of three components. Component A is a dimer with subunits of dinuclear iron with monooxygenase activity. Components B and C are electron donor and transfer sites. Like cytochrome P-450, a high valent iron-oxo complex is proposed for component A in MMO. This species abstracts a H atom from CH4 to generate a CHs" radical. 

We will compare some aspects of the reaction pathway and properties of the O2 carrier protein hemerythrin (Hr) with the early parts of the reaction cycles of the structurally related enzymes methane monooxygenase hydroxylase (MMOH) and ribonucleotide reductase (RNR). A general structural comparison of these three proteins is given in Figure 4 for the diferric and diferrous... 

Fe(IV) is an important intermediate in such heme enzymes as cytochrome c oxidase and cytochrome P450, as well as the nonheme enzymes methane monooxygenase and ribonucleotide reductase. Voltammetric studies on yeast cytochrome... 

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