Heme-containing dioxygen carriers

The hydroxylation reaction is directly effected by an enzyme-hemoprotein, monooxigenase, cytochrome P450 containing protocheme IX. The reduction of the enzyme involves flavin reductases and electron carriers, such as adrenodoxin, rubredoxin, and cytochrome b5. Dioxygen, being a weak one-electron oxidant, is activated after the reduction in the enzyme heme coordination sphere. The various forms of cytochrome P450 from liver microsomes and from Pseudomonas putida have a molecular mass of about 49000. One of the subunits of the enzyme from mitochondria of... 

Once dioxygen arrives at a cell it is reduced to water in order to yield the energy necessary to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP), the energy carrier for cell processes. This oxygen burning (8.1) is mediated in turn by a series of metalloenzymes, such as cytochrome oxidase, which contains one heme Fe and one Cu in the active site. 

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