title: Isatin: identity with the purified endogenous monoamine oxidase inhibitor tribulin.
abstract: Purified tribulin, an endogenous monoamine oxidase (MAO) inhibitor, has been identified by direct probe insertion mass spectrometry as the indole-2,3-dione, isatin. A gas chromatographic-mass spectrometric assay for isatin has been developed and used to measure its relatively high concentrations in unpurified human urine, and in rat heart and brain. Isatin is a known compound with a broad range of biological activity; this is the first report of its presence in the animal body. Isatin is a potent inhibitor of MAO, particularly of MAO B (IC50, 3 microM), and also binds to central benzodiazepine receptors (IC50 against clonazepam, 123 microM).
authors.affiliation: Department of Chemical Pathology, Queen Charlotte's Hospital, London, England.
authors.forename: V
authors.initials: V
authors.lastname: Glover
authors.forename: J M
authors.initials: JM
authors.lastname: Halket
authors.forename: P J
authors.initials: PJ
authors.lastname: Watkins
authors.forename: A
authors.initials: A
authors.lastname: Clow
authors.forename: B L
authors.initials: BL
authors.lastname: Goodwin
authors.forename: M
authors.initials: M
authors.lastname: Sandler
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007211:Indoles / Q000032:analysis*; D007510:Isatin / Q000032:analysis*; D008996:Monoamine Oxidase Inhibitors / Q000032:analysis*; D009206:Myocardium / Q000032:analysis; D051381:Rats
chemical_list: D007211:Indoles; D008996:Monoamine Oxidase Inhibitors; D007510:Isatin; C039776:tribulin