The biological clock in Gonyaulax controls luciferase activity by regulating turnover

Luciferase activity in cell-free extracts of the bioluminescent marine dinoflagellate Gonyaulax polyedra undergoes a cyclic daily change such that activities of extracts made in the middle of the night phase may be 10 times greater than in extracts of day phase cells. These cyclic changes continue under constant conditions, in a manner indicative of control by an endogenous circadian cellular mechanism. This paper describes the purification and properties of the higher molecular weight unproteolyzed luciferase from both day and night phase cells. Comparisons of the two preparations with respect to several physicochemical, enzymatic, and immunological criteria were made in order to establish the basis for the activity difference; no differences between day and night species were found. A given amount of antiluciferase inactivated the same amount of luciferase activity in both day and night extracts; their specific activities are therefore the same. These data strongly suggest that the luciferase is the same polypeptide in day and night extracts, and that such extracts contain different amounts of the enzyme. We therefore postulate that the circadian rhythm of luciferase activity is a result of biological clock-controlled synthesis and/or degradation of the luciferase polypeptide.