Quinine 3-monooxygenase

Quinine 3-monooxygenase

Quinine 3-monooxygenase is an enzyme that catalyzes the oxidation of quinine to 3-hydroxyquinine. This enzyme is part of the cytochrome P450 family, which is involved in the metabolism of various xenobiotics and endogenous compounds.

Function

Quinine 3-monooxygenase plays a crucial role in the biotransformation of quinine, a natural alkaloid used primarily for the treatment of malaria. The enzyme introduces an oxygen atom into the quinine molecule, converting it into a more polar and water-soluble form, which facilitates its excretion from the body.

Mechanism

The enzyme operates through a monooxygenase mechanism, where one atom of molecular oxygen is incorporated into the substrate (quinine) while the other atom is reduced to water. This reaction requires the presence of NADPH and cytochrome P450 reductase as cofactors.

Structure

Quinine 3-monooxygenase is a heme-containing enzyme, characteristic of the cytochrome P450 family. The heme group is essential for the enzyme's catalytic activity, as it facilitates the transfer of oxygen to the substrate.

Clinical Significance

The activity of quinine 3-monooxygenase can influence the pharmacokinetics of quinine, affecting its therapeutic efficacy and toxicity. Variations in the enzyme's activity due to genetic polymorphisms or drug interactions can lead to differences in quinine metabolism among individuals.

Related Enzymes

Quinine 3-monooxygenase is related to other members of the cytochrome P450 family, such as CYP3A4, which also metabolize a wide range of substrates, including drugs, steroids, and carcinogens.

See Also

• Cytochrome P450
• Quinine
• Malaria
• Drug metabolism
• Enzyme
• Xenobiotic