MONOAMINE OXIDASES (MAO, EC 1.4.3.4) are a family of mitochondrial enzymes that catalyze the oxidative deamination of monoamines. Two isoforms of MAO exist, MAO-A and MAO-B, with different inhibitor selectivity and tissue distribution. MAO dysfunction is thought to be responsible for a number of neurological disorders. Unusually high or low levels of MAOs in the body have been associated with depression, schizophrenia, substance abuse, attention deficit disorder, migraines, and irregular sexual maturation. MAO inhibitors are one of the major classes of drug prescribed for the treatment of depression, Parkinson's and Alzheimer's diseases. This MAO Inhibitor Screening Assay Kit provides a convenient fluorimetric means to screen for MAO enzyme inhibitors. In the assay, MAO reacts with p-tyramine, a substrate for both MAO-A and MAO-B, resulting in the formation of H2O2, which is determined by a fluorimetric Method (lambda em/ex = 585/530 nm). The assay is simple, sensitive, stable and high-throughput adaptable.