Adrenodoxin reductase: Difference between revisions
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Adrenodoxin reductase (AR) is an FAD containing flavoprotein that | Adrenodoxin reductase (AR) is an FAD containing flavoprotein that functions as an electron transfer protein in the mitochondrial P450 systems that catalyze essential steps in the biosynthesis of steroid hormones.<ref name="HI-review">PMID:22217824</ref> | ||
The enzyme nomenclature code of AR is [http://www.chem.qmul.ac.uk/iubmb/enzyme/EC1/18/1/6.html 1.18.1.6]. | |||
==Mitochondrial P450 systems== | |||
Mitochondrial P450 systems are composed of three proteins: | |||
* Adrenodoxin reductase | |||
* Adrenodoxin, a [2Fe-2S] ferredoxin type iron-sulfur protein | |||
* Mitochondrial P450 | |||
The reactions catalyzed by P450 type enzymes are called monooxygenation reactions because P450 catalyzes incorporation of only one atom of molecular O<sub>2</sub> into substrate (S) while reducing the second atom of O into H<sub>2</sub>O with the following stoichiometry: | |||
SH + O<sub>2</sub> + NAD(P)H + H<sup>+</sup> → ROH + H<sub>2</sub>O + NAD(P)<sup>+</sup> | |||
In the mitochondrial P450 systems, the source of electrons is NADPH. The main function of AR in these systems is to accept two electrons from NADPH and to transfer them one at time to adrenodoxin. Reduced adrenodoxin in turn reduces mitochondrial P450s that catalyze essential steps in the biosynthesis of steroids, such as cleavage of the side chain of cholesterol producing pregnenolone, and C11- and C18 hydroxylation steroids producing cortisol and aldosterone.<ref name="HI-review" /> | |||
==History== | |||
==References== | ==References== | ||