Final answer:
Catecholamines are inactivated by Catechol-O-Methyl-Transferase (COMT) and Mono-Amine Oxidase (MAO) and metabolized into O-methylated and deaminated metabolites.
Step-by-step explanation:
Catecholamines are inactivated by Catechol-O-Methyl-Transferase (COMT) and Mono-Amine Oxidase (MAO). These enzymes metabolize catecholamines in the liver into O-methylated and deaminated metabolites, which are then excreted as waste products, such as Vanillylmandelic acid (VMA).