The Firefly Squid Watasenia scintillans

Harvey (1917) noted that the fresh arm photophores of Watasenia scintillans do not show a luciferin-luciferase reaction, and Shoji (1919) using a gas chamber of purified hydrogen demonstrated that molecular oxygen is needed for the luminescence. 

Goto et al. (1974) extracted the arm photophores, and isolated a compound that is highly fluorescent in blue. They determined the structure of this compound to be coelenteramide disulfate (structure A below), and named it Watasenia oxyluciferin. Then, Inoue et al. (1975) 

Watasenia oxytuciferin Watasenia prelucifenn Watasenia luciferin 

The absorption spectra of Watasenia luciferin (coelenterazine disulfate) and Watasenia oxyluciferin (coelenteramide disulfate) are shown in Fig. 6.3.2. Watasenia luciferin in neutral aqueous solutions is auto-oxidized in air more rapidly than coelenterazine, and the compound emits a strong chemiluminescence in the presence of H2O2 ( 10mM) plus Fe2+ ( 0.2mM). Watasenia oxyluciferin is strongly fluorescent in aqueous solutions (Amax 400 nm), 500 times stronger than the fluorescence of coelenteramide in aqueous media (Goto et al., 1974). 

Involvement of ATP in the luminescence. Tsuji (1985) found that homogenate of the light organs of W. scintillans emits light when ATP is added in the presence of Mg2+. The luminescence reaction has a sharp pH optimum at 8.8 (Fig. 6.3.3), and the luminescence spectrum shows a peak at 470 nm (Fig. 6.3.4). The luminescence reaction 

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Tsuji, F. I. (1985). ATP-dependent bioluminescence in the firefly squid, Watasenia scintillans. Proc. Natl. Acad. Sci. USA 82 4629-4632. 

Tsuji, F. I. (2002). Bioluminescence reaction catalyzed by membrane-bound luciferase in the firefly squid Watasenia scintillans. Biochim. Biophys. Acta 1564 189-197. 

BIOLUMINESCENCE REACTION IN THE FIREFLY SQUID, WATASENIA SCINTILLANS... 

Tsuji F I. Role of molecular oxygen in the bioluminescence of the firefly squid, Watasenia scintillans. Biochem Biophys Res Commun 2005 338 250-53. 

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