Monoamine oxidase

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Monoamine oxidase (MAO) is an enzyme that catalyzes the oxidation of monoamines. They are found bound to the outer membrane of mitochondria in most cell types in the body. The enzyme was originally discovered by Mary Bernheim in the liver and was named tyramine oxidase.

Function[edit | edit source]

Monoamine oxidases play a vital role in the breakdown of monoamines in neurotransmitters such as dopamine, norepinephrine, and serotonin. They also assist in the metabolism of many drugs and toxins. The activity of the monoamine oxidase enzyme is vital for maintaining proper mental and physical health.

Types[edit | edit source]

There are two types of MAO: MAO-A and MAO-B. Both are found in neurons and astroglia. Outside the central nervous system, both types of MAO are also found in the liver, intestinal mucosa, and placenta.

MAO-A[edit | edit source]

MAO-A primarily degrades serotonin, melatonin, norepinephrine, and epinephrine.

MAO-B[edit | edit source]

MAO-B primarily degrades phenethylamine and certain other trace amines. In humans, it is selectively inhibited by selegiline.

Clinical significance[edit | edit source]

Abnormalities in the function of MAO are linked to a variety of psychiatric and neurological disorders. For example, an excess of MAO-A activity is associated with depression and certain types of anxiety, while a deficiency is associated with aggression and attention deficit disorder.

Inhibitors[edit | edit source]

MAO inhibitors are used to treat depression, anxiety, and Parkinson's disease. They work by blocking the action of MAO, thereby increasing the availability of monoamine neurotransmitters in the brain.

See also[edit | edit source]

Monoamine oxidase Resources
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