title: An investigation of the active site of lactate dehydrogenase with NAD+ analogues.
abstract: The kinetic properties of 18 NAD+ analogues, with alterations to the nicotinamide moiety, have been studied with respect to dogfish, M4, rabbit M4 and beef H4 lactate dehydrogenase. The size of the groups present at C-3 of the pyridinium can be increased quite extensively without loss of coenzyme activity. Groups tested were thioamide, methyl, ethyl, diazoketone and chloroacetyl. Substitutions at positions C-4 and C-5 prevent proper positioning for hydride transfer and can hinder binding to the enzyme. The kinetic properties of pyridine-adenine dinucleotide and its 3-iodo derivative reveal the binding role of the amide at C-3 whereas 3-cyanopyridine-adenine dinucleotide is a strong inhibitor.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003067:Coenzymes / Q000378:metabolism; D004284:Dogfish; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D011817:Rabbits; D013045:Species Specificity
chemical_list: D003067:Coenzymes; D009243:NAD; D007770:L-Lactate Dehydrogenase