Isolation and Properties of the Luciferase Stored in the Ovary of the Scyphozoan Medusa Periphylla periphylla

Abstract

Bioluminescence of the medusa Periphylla is based on the oxidation of coelenterazine catalyzed by luciferase. Periphylla has two types of luciferase: the soluble form luciferase L, which causes the exumbrellar bioluminescence display of the medusa, and the insoluble aggregated form, which is stored as particulate material in the ovary, in an amount over 100 times that of luciferase L. The eggs are especially rich in the insoluble luciferase, which drastically decreases upon fertilization. The insoluble form could be solubilized by 2-mercaptoethanol, yielding a mixture of luciferase oligomers with molecular masses in multiples of approximately 20 kDa. Those having the molecular masses of 20 kDa, 40 kDa, and 80 kDa were isolated and designated, respectively, as luciferase A, luciferase B, and luciferase C. The luminescence activities of Periphylla luciferases A, B, and C were 1.2 approximately 4.1 x 10(16) photon/mg. s, significantly higher than any coelenterazine luciferase known, and the quantum yields of coelenterazine catalyzed by these luciferases (about 0.30 at 24 degrees C) are comparable to that catalyzed by Oplophorus luciferase (0.34 at 22 degrees C), which has been considered the most efficient coelenterazine luciferase until now. Luciferase L (32 kDa) could also be split by 2-mercaptoethanol into luciferase A and an accessory protein (approx. 12 kDa), as yet uncharacterized. Luciferases A, B, and C are highly resistant to inactivation: their luminescence activities are only slightly diminished at pH 1 and pH 11 and are enhanced in the presence of 1 approximately 2 M guanidine hydrochloride; but they are less stable to heating than luciferase L, which is practically unaffected by boiling.