P450 Cytochrome

P450 Cytochrome’s mechanism of action of enzyme activity can be explained in a series of simple chemical steps:

1. Substrate trapping begins to cytochrome ferric (Fe3 +).
2. An electron is transferred to the Fe atom, moving it to its ferrous state (Fe2 +), this transfer is often carried out by protein cytochrome b5 (Figure 1).
3. The ferrous form binds to a molecule of O2.
4. A second reduction is done by adding an electron and a proton.
5. This intermediate loses a water molecule leaving a complex (FeO) 3 + that directly oxidizes the substrate.

Figure 4 shows some of the possible origins of electrons involved in the process described here. The P450 was found in the membrane of the endoplasmic reticulum (a cellular organelle of most animal cells). The electrons involved in the oxidation of substrates in the hands of cytochrome P450 may come from or NADPH (nicotinamide adenine dinucleotide phosphate) from the cytoplasm or cytochrome b5 which is located in the membrane (Guengerich, 1993).