title: The properties of B-form monoamine oxidase in mitochondria from monkey platelet.
abstract: The present study was examined the effect of the properties of monkey platelet monoamine oxidase (MAO) based on inhibitor sensitivity. Monkey platelet showed a high MAO activity with beta-phenylethylamine (beta-PEA) as substrate and a very low A-form MAO activity with 5 hydroxytryptamine (5-HT) as substrate. Moreover, monkey platelet MAO was sensitive to the drugs deprenyl as B-form MAO inhibitor and less sensitive to clorgyline and harmaline as A form MAO inhibitor with beta-PEA as the B-form MAO substrate. B-form MAO from monkey platelet was more stable against heat treatment at 55 degrees C than B-form MAO in brain. After digestion with trypsin at 37 degrees C for 4 hrs, it was found that MAO from platelet was inhibited about 70% with beta-PEA as substrate with brain. The tricyclic antidepressant imipramine and nortriptyline inhibited B-form MAO activity more potency than B-form MAO in brain. However, when the noncyclic antidepressant nomifensine was used, monkey platelet B-form MAO activities were less potently inhibited. All these reagents were noncompetitive inhibitors of B form MAO in monkey platelet. The present studies demonstrated that monkey platelet MAO is a single of B-form MAO and sensitive to tricyclic antidepressants.
authors.forename: Toshio
authors.initials: T
authors.lastname: Obata
authors.forename: Masahiro
authors.initials: M
authors.lastname: Aomine
mesh_terms: D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology; D001792:Blood Platelets / Q000201:enzymology* / Q000648:ultrastructure; D000882:Haplorhini; D008928:Mitochondria / Q000201:enzymology*; D008995:Monoamine Oxidase / Q000187:drug effects / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*
chemical_list: D000929:Antidepressive Agents, Tricyclic; D008996:Monoamine Oxidase Inhibitors; D008995:Monoamine Oxidase