Bioluminescence reaction catalyzed by membrane-bound luciferase in the "firefly squid," Watasenia scintillans.
The small Japanese "firefly squid," Watasenia scintillans, emits a bluish luminescence from dermal photogenic organs distributed along the ventral aspects of the head, mantle, funnel, arms and eyes. The brightest light is emitted by a cluster of three tiny organs located at the tip of each of the fourth pair of arms. Studies of extracts of the arm organs show that the light is due to a luciferin-luciferase reaction in which the luciferase is membrane-bound. The other components of the reaction are coelenterazine disulfate (luciferin), ATP, Mg(2+), and molecular oxygen. Based on the results, a reaction scheme is proposed which involves a rapid base/luciferase-catalyzed enolization of the keto group of the C-3 carbon of luciferin, followed by an adenylation of the enol group by ATP. The AMP serves as a recognition moiety for docking the substrate molecule to a luciferase bound to membrane, after which AMP is cleaved and a four-membered dioxetanone intermediate is formed by the addition of molecular oxygen. The intermediate then spontaneously decomposes to yield CO(2) and coelenteramide disulfate (oxyluciferin) in the excited state, which serves as the light emitter in the reaction.
Tsuji
Frederick I
FI
Marine Biology Research Division 0202, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093, USA. ftsuji@ucsd.edu
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D049832:Decapodiformes / Q000201:enzymology*; D011756:Diphosphates / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D049454:Firefly Luciferin / Q000378:metabolism; D007093:Imidazoles; D008156:Luciferases / Q000378:metabolism*; D008163:Luminescent Measurements; D008956:Models, Chemical; D009928:Organ Specificity; D010100:Oxygen / Q000378:metabolism; D011719:Pyrazines / Q000378:metabolism / Q000494:pharmacology
D011756:Diphosphates; D007093:Imidazoles; D011719:Pyrazines; C017144:coelenterazine; D049454:Firefly Luciferin; D000255:Adenosine Triphosphate; D008156:Luciferases; C003319:sodium pyrophosphate; D010100:Oxygen