MAOB and nervous system disorder: It binds irreversibly to the enzyme monoamine oxidase B (MAO-B), which is primarily located in astrocytes.1, , –4 L-deprenyl (selegiline) is a selective and irreversible inhibitor of MAO-B.5,6 Elevated levels of MAO-B density and activity serve as biological markers for various neurological disorders and brain abnormalities.