What is cytochrome P450 3A4 system?
Cytochrome P450 3A4 (abbreviated CYP3A4) (EC 1.14. 13.97) is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body.
What phase is cytochrome P450?
Cytochromes P450 (CYP) are responsible for their phase 1 metabolism in mammals, with metabolism in humans being mediated by several, including CYP1A2, CYP3A5, and CYP3A4.
What is cytochrome P450 pathway?
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown.
What happens when CYP450 is inhibited?
IRREVERSIBLE INHIBITION In some cases, CYP450 inhibition is irreversible. The formation of a stable complex, between a drug and the metabolizing enzyme, is one mechanism that can result in irreversible inhibition. The inhibitor can be a drug or one of its metabolites.
Which is cyp450 inhibitor?
Examples of Common Drug-Drug Interactions Involving the Cytochrome P450 Enzyme System
| Drug(s)/product | Enzyme inhibitor or inducer |
|---|---|
| Fluoxetine (Prozac), paroxetine (Paxil), | CYP2D6 inhibitor |
| Grapefruit juice | CYP3A4 inhibitor |
| Metronidazole (Flagyl) | CYP2C9 inhibitor |
| Terbinafine (Lamisil) | CYP2D6 inhibitor |
Where does Phase 1 and Phase 2 metabolism occur?
The majority of biotransformation takes place within the liver in cells called hepatocytes. However, several of the enzymes for phase I, phase II, and phase III reactions can also occur in extrahepatic tissues, such as adipose, intestine, kidney, lung, and skin.