title: Demethylation of O-methyl metabolites of catecholamines in erythrocytes: a methanol-forming reaction.
abstract: When lysates of erythrocytes of 11 species, including man, were incubated at pH 7.8 with L-3-methoxy-4-hydroxy [U-14C]phenylalanine or with [7-3H]normetanephrine, these were demethylated and formed 3,4-dihydroxy[14C]phenylalanine or [3H]norepinephrine. These catechols were identified by column and paper chromatographic methods. When [14C-methoxy]normetanephrine was incubated with lysates of rat erythrocytes, the one-carbon product was identified as [14C]methanol by the isolation in the incubation mixture of [14C]methanol-3,5-dinitrobenzoate and its recrystallization to constant specific radioactivity. Metanephrine, 3-methoxytyramine, vanilmandelic acid, and 3-methoxy-4-hydroxyphenylglycol were also O-demethylated by rat erythrocytes; epinephrine was not N-demethylated. The reaction was not influenced by the addition of S-adenosylmethionine. The reaction appears to be different from that catalyzed by the "methanol-forming enzyme" previously described in erythrocytes and in other tissues.
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood; D002395:Catecholamines / Q000097:blood*; D002415:Cats; D002417:Cattle; D010856:Columbidae; D003640:Dealkylation; D004285:Dogs; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism*; D005557:Formaldehyde / Q000097:blood; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D000432:Methanol / Q000097:blood*; D051379:Mice; D010090:Oxidoreductases, O-Demethylating / Q000378:metabolism; D011485:Protein Binding; D011817:Rabbits; D051381:Rats; D012756:Sheep; D001503:Ursidae
chemical_list: D001798:Blood Proteins; D002395:Catecholamines; D002245:Carbon Dioxide; D005557:Formaldehyde; D010090:Oxidoreductases, O-Demethylating; D000432:Methanol