Monoamine oxidase A is an isozyme of monoamine oxidase. It preferentially deaminates norepinephrine (noradrenaline), epinephrine (adrenaline), serotonin, and dopamine (dopamine is equally deaminated by MAO-A and MAO-B). It is inhibited by clorgiline and befloxatone.This gene encodes monoamine oxidase A
, an enzyme that degrades amine neurotransmitters, such as dopamine, norepinephrine, and serotonin. The protein localizes to the outer mitochondrial membrane. The gene is adjacent to a related gene (MAOB) on the opposite strand of chromosome X. Mutation in this gene results in monoamine oxidase deficiency, or Brunner syndrome. MAO-A levels in the brain as measured using positron emission tomography are elevated by an average of 34 percent in patients with major depressive disorder.