Modified: May 22, 2022
monoamine oxidase
This page is from my personal notes, and has not been specifically reviewed for public consumption. It might be incomplete, wrong, outdated, or stupid. Caveat lector.A monoamine oxidase (MAO) is an enzyme that breaks down mono-amine neurotransmitters such as dopamine, serotonin, norepinephrine, and various psychedelic drugs.
Specifically, it facilitates the 'attack' of the amine site by an oxygen radical, replacing it with an O or OH group and cleaving off an ammonia (or related amine) molecule.
Humans have two main monoamine oxidase enzymes, MAO-A and MAO-B.
Drugs that inhibit one or both of these enzymes are called monoamine oxidase inhibitors (MAOIs). Preventing monoamine breakdown is a 'big hammer' since there are so many monoamines and they do all kinds of things. MAOIs can be powerful antidepressants, but they tend to have dangerous dietary and drug interactions, because some monoamines can do bad stuff if we don't metabolize them (for example, tyramine, found in cheeses and fermented foods, leads to hypertensive crisis in large concentrations)