Last modified: Mon May 10 11:16:57 BST 2004
All the multicomponent electron transfer chains which contain P450 are termed here P450-containing systems (for a list of relevant papers, click here). P450-containing systems primarily fall into two major classes: bacterial/mitochondrial (type I), and microsomal (type II). Alternatively, P450-containing systems can be classified according to the number of their protein components. Mitochondrial and most bacterial P450 systems have three components: an FAD-containing flavoprotein (NADPH or NADH-dependent reductase), an iron-sulphur protein, and P450. The eukaryotic microsomal P450 system contains two components: NADPH:P450 reductase (a flavoprotein containing both FAD and FMN) and P450; and a soluble monooxygenase P450BM-3 from Bacillus megaterium exists as a single polypeptide chain with two functional parts (the haem and flavin domains), and represents a unique bacterial one-component system - sequence and functional comparisons show that these domains are more similar to P450 and the flavoprotein of the microsomal two-component P450 monooxygenase system than to the relevant proteins of the three-component system.
To get an idea of P450-containing systems, have a look at graphic representation of their domain structure or table presenting families of structural domains.
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