 Ohfune and Tomita, who wanted to investigate its absolute stereochemistry, were the first and only to synthesize domoic acid in 1982.In 1999, using 13C- and 14C-labelled precursors, the biosynthesis of domoic acid in the diatom genus "Pseudo-nitzschia" was examined.After addition of [1,2-13C2]-acetate, NMR spectroscopy showed enrichment of every carbon in domoic acid, indicating incorporation of the carbon isotopes.