CYP450 enzymes are a superfamily of heme-thiolate proteins that catalyze the oxidation of organic substances. They are involved in the metabolic biotransformation of a wide range of exogenous and endogenous compounds. The enzymes facilitate the introduction of an oxygen atom into a substrate, making it more hydrophilic and easier to excrete. This process is known as phase I metabolism. There are over 50 different CYP450 enzymes in humans, but the majority of drug metabolism is carried out by just a few, including CYP3A4, CYP2D6, CYP2C9, and CYP1A2.
