Tracer studies on dinoflagellate luciferin with [15N]-glycine and [15N]-l-glutamic acid in the dinoflagellate Pyrocystis lunula

The bioluminescence of dinoflagellate is a typical luciferin–luciferase reaction. To clarify the biosynthesis of dinoflagellate luciferin, we performed a feeding experiment with [15N]-glycine and [15N]-l-glutamic acid in the dinoflagellate Pyrocystis lunula. In a control experiment, we also examined whether or not chlorophyll a was incorporated with these labeled compounds. We detected by mass spectrometry the incorporation of [15N]-glycine and [15N]-l-glutamic acid into the four tetrapyrrole rings of the luciferin. In the control experiment, chlorophyll a was also incorporated with [15N]-glycine and [15N]-l-glutamic acid. Our results show that either glycine or glutamic acid could be the original component of dinoflagellate luciferin as well as chlorophyll a in the dinoflagellate P. lunula.