Folates as inhibitors of glutamate dehydrogenase.
Folates and tetrahydrofolates inhibit beef liver glutamate dehydrogenase (EC 1.4.1.2). Double reciprocal plats indicate a competitive inhibition for alpha-ketoglutarate-glutamate by folic acid and methotrexate and a complex or mixed type for NAD-NADH site. Pteroic acid is not inhibitory at the concentrations studied. The addition of up to four gamma-linked glutamyl residues to folic and tetrahydrofolic acids increases the inhibition. Further chain elongation of the gamma-peptide had no effect on the inhibitory activity. The p-aminobenzoate poly-gamma-glutamates were less inhibitory than the corresponding folyl polyglutamates.
D062365:Aminobenzoates / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D005492:Folic Acid / Q000494:pharmacology*; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors*; D005971:Glutamates / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008727:Methotrexate / Q000494:pharmacology; D009243:NAD / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D011622:Pterins / Q000494:pharmacology; D013763:Tetrahydrofolates / Q000494:pharmacology
D062365:Aminobenzoates; D005971:Glutamates; D010455:Peptides; D011622:Pterins; D013763:Tetrahydrofolates; D009243:NAD; C005584:pteroic acid; D005492:Folic Acid; D005969:Glutamate Dehydrogenase; D008727:Methotrexate