CYP2B6

Cytochrome P450 2B6 is an is_associated_with::enzyme that in humans is encoded by the CYP2B6 is_associated_with::gene. CYP2B6 is a member of the is_associated_with::Cytochrome P450 group of enzymes. Along with is_associated_with::CYP2A6, it is involved with metabolizing is_associated_with::nicotine, along with many other substances.

Function
This gene, CYP2B6, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are is_associated_with::monooxygenases which catalyze many reactions involved in drug is_associated_with::metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the is_associated_with::endoplasmic reticulum and its expression is induced by is_associated_with::phenobarbital. The enzyme is known to metabolize some is_associated_with::xenobiotics, such as the anti-cancer drugs cyclophosphamide and ifosphamide.

Gene
Transcript variants for this gene have been described; however, it has not been resolved whether these transcripts are in fact produced by this gene or by a closely related is_associated_with::pseudogene, CYP2B7. Both the gene and the pseudogene are located in the middle of a CYP2A pseudogene found in a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q.

CYP2B6 Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP2B6.

Inhibitors of CYP2B6 can be classified by their potency, such as:
 * Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
 * Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
 * Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.