Cytochrome P450s, their multiple forms

Bhagwat SV, Boyd MR, Ravindranath V. 1995a. Brain mitochondrial cytochromes P450 xenobiotic metabolism, presence of multiple forms and their selective inducibility. Arch Biochem Biophys 320 73-83. 

Class III peroxidases have been the subject of numerous studies [10] and applications [11], since their extraordinary catalytic properties make them a valuable catalytic tool in the plant cell chemical factory, and in organic synthesis. In fact, class III peroxidases, together with other oxidative enzymes, such as cytochrome P450s and oxygenases [12], appear to be the main driving force in the evolution of plant metabolic pathways because individual enzymes can typically accept multiple substrates and form several products. This metabolic plasticity of class III peroxidases, paradoxically, has frequently led to misunderstanding of its vital function in the plant cell biochemical factory. 

The discovery of c5 ochromes P450 in mammalian tissues rich with these proteins, such as liver and the adrenal gland, resulted in intense scrutiny of their roles in xenobiotic metabolism and endogenous functions. Following their discovery came the realization that mammalian proteins required electron donor systems for activity, either NADPH-cytochrome P450 reductase (CPR) or adrenodoxin and adrenodoxin reductase in the endoplasmic reticulum or the mitochondria respectively Protein biochemistry and molecular biology revealed the multiplicity of CYP forms and mammalian genomes exhibited CYP diversity. 

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