MAOA, Monoamine oxidase-A is an FAD-dependent mitochondrial enzyme, which, together with its isoenzyme MAO-B, catalyses the oxidative deamination of structurally diverse amines. MAOA is mainly involved in the metabolism of monoamine neurotransmitters, such as such as serotonin, dopamine, and norepinephrine. Inhibitors of MAOA are in clinical use for affective disorders and is approved to treat despression.