Amine oxidase [flavin-containing] A (MAO-A)

Amine oxidase [flavin-containing] A (MAO-A) is a mitochondrial enzyme responsible for the oxidative deamination of biogenic and xenobiotic amines, with a high affinity for serotonin, norepinephrine, and epinephrine. It is predominantly expressed in the brain, gastrointestinal tract, and liver, where it serves as a critical regulator of neurotransmitter levels and a metabolic barrier against dietary amines like tyramine. In the central nervous system, MAO-A activity directly influences mood and emotional behavior; consequently, its overactivity is strongly linked to major depressive disorder and anxiety. Conversely, a genetic deficiency of MAO-A results in Brunner syndrome, a condition characterized by impulsive aggression and cognitive impairment. Pharmacological inhibition of MAO-A by monoamine oxidase inhibitors (MAOIs) is an established therapeutic strategy for treatment-resistant depression, though it requires strict dietary and medicinal management to prevent life-threatening hypertensive crises or serotonin syndrome. Beyond psychiatry, MAO-A is increasingly recognized for its role in neurodegenerative diseases and certain cancers due to the production of hydrogen peroxide as a metabolic byproduct, which contributes to oxidative stress and cellular damage.

Other names

Monoamine oxidase type AMAOAMonoamine oxidase A

Inhibition of the oxidative deamination of monoamine neurotransmitters, leading to increased synaptic concentrations of serotonin, norepinephrine, and dopamine.