The FMO3 gene provides instructions for making an enzyme that is part of a larger enzyme family called flavin-containing dimethylaniline monooxygenases (FMOs). These enzymes break down compounds that contain nitrogen, sulfur, or phosphorus. The FMO3 enzyme, which is made chiefly in the liver, is responsible for breaking down nitrogen-containing compounds derived from the diet.
One of these compounds is trimethylamine, which is the molecule that gives fish their fishy smell. Trimethylamine is produced as bacteria in the intestine help digest certain proteins obtained from eggs, liver, legumes (such as soybeans and peas), certain kinds of fish, and other foods. The FMO3 enzyme normally converts fishy-smelling trimethylamine into another compound, trimethylamine-N-oxide, which has no odor. Trimethylamine-N-oxide is then excreted from the body in urine.
Researchers believe that the FMO3 enzyme also plays a role in processing some types of drugs. For example, this enzyme is likely needed to break down the anticancer drug tamoxifen, the anti-inflammatory medication benzydamine, the antifungal drug ketoconazole, and certain medications used to treat depression (antidepressants).
The FMO3 enzyme may also be involved in processing nicotine, an addictive chemical found in tobacco. Normal variations (polymorphisms) in the FMO3 gene may affect the enzyme’s ability to break down these substances. Researchers are working to determine whether FMO3 polymorphisms can help explain why people respond differently to certain drugs.
Other Names
Dimethylaniline monooxygenase [N-oxide-forming] 3; Dimethylaniline oxidase 3; FMO3_HUMAN; FMOII
Related Genetics Topics
Identifiers
- NCBI Gene: 2328
- OMIM: 136132
Source: MedlinePlus Genetics, U.S. National Library of Medicine.
