title: Tetrahydrofolic acid: an inhibitor of the methyltetrahydrofolic acid-mediated methylation of indolethylamines.
abstract: Tetrahydrofolic acid exerts a product inhibition on the methyltetrahydrofolic acid-mediated methylation of indolethylamines. Kinetic studies showed that this inhibition was competitive with respect to methyltetrahydrofolic acid and non-competitive with respect to N-methylserotonin. Chromatographic separation of S-adenosylmethionine-dependent indolethylamine N-methyltransferase and methyltetrahydrofolic acid-dependent methyltransferase from rabbit lung was obtained. There was no cross reaction of the two enzymes to tetrahydrofolic acid, S-adenosylhomocysteine, N, N-dimethyltryptamine or bufotenin.
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D002027:Bufotenin / Q000494:pharmacology; D005021:Ethylamines / Q000378:metabolism*; D006710:Homocysteine / Q000494:pharmacology; D007211:Indoles / Q000378:metabolism; D008168:Lung / Q000201:enzymology*; D008745:Methylation; D008780:Methyltransferases / Q000037:antagonists & inhibitors*; D004130:N,N-Dimethyltryptamine / Q000494:pharmacology; D011817:Rabbits; D012436:S-Adenosylmethionine; D012701:Serotonin / Q000494:pharmacology; D013763:Tetrahydrofolates / Q000494:pharmacology*
chemical_list: D005021:Ethylamines; D007211:Indoles; D013763:Tetrahydrofolates; D002027:Bufotenin; D006710:Homocysteine; D012701:Serotonin; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D000241:Adenosine; D004130:N,N-Dimethyltryptamine