Both types of MAOs live in the brain, but they hang out in different kinds of cells. MAO-A is found in catecholaminergic neurons, while MAO-B is found in serotonergic neurons.They have a hang-out place in common, and this is inside the astroglial cells, which are essentially the janitors that clean up all the mess that cells make in the brain.
As we travel further down in the body, we will find the MAO-A is localized in the placenta, liver, and gastro-intestinal tract, but MAO-B is found spread out in the body in blood platelets and the central nervous system. This means that MAO-B is much easier to access, since it requires only a blood test, instead of grubbing around with a personšs internal organs to get a hold of their MAO-A.
If you want to know where to find MAO enzymes inside a cell, look for the mitochondria. You will find the enzymes bonded covalently to the polypeptides on their outer membranes.
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