[Inhibition of luciferase from the firefly Luciola mingrelica by ATP analogs]

The effects of the ATP analogs--nucleotide bases, nucleosides, nucleotide 5'-mono, 5'-di- and 5'-triphosphates -- on the bioluminescence of luciferin oxidation in the presence of firefly (Luciola mingrelica) luciferase were studied. It was shown that all the compounds tested are luciferase inhibitors, differing in terms of inhibition mechanisms. The inhibition by all the ATP analogs is non-competitive with respect to luciferin, the Ki values varying from 0.3 to 56 mM. With respect to ATP the nucleotide bases, nucleosides and 5'-diphosphates are non-competitive inhibitors, whereas nucleotide 5'-mono- and 5'-triphosphates are inhibitors of the mixed type. The Ki values vary from 0.02 to 220 mM, depending on the inhibitor structure. The non-competitive inhibition is influenced by binding two inhibitor molecules to an enzyme molecule. An allosteric mechanism of luciferase inhibition by ATP analogs is proposed and possible functioning of the ATP-binding site on the enzyme is discussed.