Tele-Methylhistamine is a specific MAO B substrate in man.
Tele-methylhistamine, the first metabolite of histamine in tissues which lack diamine oxidase, is shown to be a substrate for human MAO B. Human liver homogenates were incubated with 3H-tele-methylhistamine and the products separated using thin-layer chromatography. The major product was 3-methylimidazoleacetic acid, the oxidatively deaminated metabolite of tele-methylhistamine. The reaction was inhibited by low concentrations of (-)deprenyl, the specific MAO B inhibitor. Tele-methylhistamine was also found to inhibit competitively the oxidation of phenylethlamine, but not that of 5-hydroxytryptamine, providing further evidence that it is oxidized by MAO B itself and not a related enzyme. This finding implies that (-)deprenyl and other MAO inhibitors used clinically may interfere with histamine metabolism.
D001667:Binding, Competitive; D003641:Deamination; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008761:Methylhistamines / Q000378:metabolism*; D008995:Monoamine Oxidase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010627:Phenethylamines / Q000494:pharmacology; D012642:Selegiline / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism
D008761:Methylhistamines; D010627:Phenethylamines; D012642:Selegiline; D012701:Serotonin; D008995:Monoamine Oxidase; C020404:tele-methylhistamine