Biosynthesis of Cypridina Luciferin in Cypridina noctiluca

Luminescence in the marine ostracods Cypridina noctiluca and Vargula hilgendorfii is produced by Cypridina luciferin-luciferase reaction.In this study, a feeding experiment with stable isotope-labeled amino acids was performed in C. noctiluca.The results of LC/ESI-MS analyses indicated that C. noctiluca is able to synthesize Cypridina luciferin de novo from three amino acids (L-tryptophan, L-isoleucine, and L-arginine).Luminescence in living animals is produced principally through luciferin-luciferase reaction. 1In marine organisms, the chemical structures of several luciferins have been determined, including coelenterazine, 2 Watasenia luciferin, 3 Cypridina luciferin, 4 krill luciferin, 5 and dinoflagellate luciferin. 6The well-characterized luciferins are imidazopyrazinone (3,7-dihydroimidazopyrazin-3-one) compounds such as coelenterazine and Cypridina luciferin, and they are distributed in various marine animals. 1,7,8,9minous ostracods have been found in the genera of Vargula, Cypridina, Pyrocypris and Conchoecia. 1,10,11Vargula, Cypridina and Pyrocypris are classified in the family Cypridinidae and the luciferin for luciferase reaction is Cypridina luciferin. 10Conchoecia is classified in the family Halocyprididae and the luciferin for luciferase reaction is coelenterazine. 8,9,12As previously proposed, 4,13 imidazopyrazinone-type luciferins would be biosynthesized from three amino acids (i.e., arginine, isoleucine and tryptophan for Cypridina luciferin; phenylalanine and two tyrosines for coelenterazine).[16] However, the biosynthesis of Cypridina luciferin in other species such as Cypridina and Pyrocypris has