Monoamine Oxidase (MAO) is widely present in mitochondria of liver, kidney, brain, small intestine and other organ cells, and mainly participates in metabolic inactivation of bioactive amine substances. MAO is divided into two subtypes, MAO-A and MAO-B, based on the binding specificity of substrates or inhibitors, cell distribution, and immune specificity. MAO can catalyze the corresponding substrate to produce H<sub>2</sub>O<sub>2</sub>, and H<sub>2</sub>O<sub>2</sub> further forms a red complex with the fluorescent probe under the action of the enzyme. The change of the fluorescence value of the sample at the excitation wavelength of 535 nm and the emission wavelength of 587 nm in unit time can be measured, and the activity of MAO-A and MAO-B of the sample can be detected and calculated by inhibiting it with specific inhibitors.
