title: Nicotinamide methyltransferase inhibition by S-adenosylethionine.
abstract: An assay for nicotinamide methyltransferase which uses an Affi-Gel 601 boronate column to separate substrate from product has been used to study the inhibition of the nicotinamide methylase. S-Adenosylethionine and S-adenosylhomocysteine inhibited the enzyme in a dose dependent fashion. Five times more S-adenosylethionine than S-adenosylhomocysteine was necessary for 50% inhibition of the enzyme. Data from a substrate concentration curve supports a competitive type of inhibition for both inhibitors. It is proposed that this inhibition may alter liver levels of nicotinamide and the urinary excretion of N1-methylnicotinamide.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D005001:Ethionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008780:Methyltransferases / Q000037:antagonists & inhibitors*; D050903:Nicotinamide N-Methyltransferase; D051381:Rats; D011919:Rats, Inbred Strains; D012435:S-Adenosylhomocysteine / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: C012167:S-adenosylethionine; D012435:S-Adenosylhomocysteine; D008780:Methyltransferases; D050903:Nicotinamide N-Methyltransferase; D000241:Adenosine; D005001:Ethionine