ADP is produced by firefly luciferase but its synthesis is independent of the light emitting properties.
During experiments aimed at understanding the time course of appearance of reaction products in the Photinus pyralis luciferase system, an expected compound with a typical nucleotide UV spectrum was isolated. According to capillary electrophoresis (CE) analysis and 1H, 31P-NMR spectra, it was unambiguously found to be ADP, either with extracted or recombinant enzymes. The ADP synthesis was demonstrated by standard UV spectrophotometric methods and CE analysis. Also, the luciferase produced AMP and ATP from ADP. This reaction was completely inhibited by Ap(5)A at 250 nM and was independent of the light emitting properties of the enzyme. The only catalytic mechanism to explain the production of ADP is an intrinsic adenylate kinase activity of luciferase. The K(m) values of the AK activity are 0.3, 0.7, 0.06 mM for AMP, ADP, and ATP respectively. The multiple enzyme activities of luciferase may be partly responsible for the complex kinetics of light emission by changing the nucleotide concentrations.
Min
K
K
Lady Davis Institute for Medical Research, Room 231, Sir Mortimer B. Davis-Jewish General Hospital, 3999 cote-Sainte-Catherine road, PQ H3T 1E2, Montreal, Canada. klmin@sympatico.ca
Steghens
J
J
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000263:Adenylate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D002852:Chromatography, Ion Exchange; D001517:Coleoptera / Q000201:enzymology*; D015226:Dinucleoside Phosphates / Q000378:metabolism / Q000494:pharmacology; D019075:Electrophoresis, Capillary; D049454:Firefly Luciferin / Q000378:metabolism; D007700:Kinetics; D008027:Light; D008156:Luciferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008163:Luminescent Measurements
D015226:Dinucleoside Phosphates; D000249:Adenosine Monophosphate; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; D049454:Firefly Luciferin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008156:Luciferases; D000263:Adenylate Kinase