AbstractThe distribution of kainic acid among various red algae was investigated. Analysis of free amino acids from different populations of Palmaria palmata showed that some were unable to accumulate kainic acid to detectable concentrations, whereas in two dwarf mutants it was a major component of the free amino acid composition. The amino acid profiles were also examined for unknown amino acids in the search for possible intermediates in kainic acid biosynthesis. The only unknown amino acid present in P. palmata extracts was isolated and identified by NMR spectroscopy as 1′‐hydroxykainic acid. This compound was found in all samples that contained kainic acid. To investigate the effect of growth conditions on kainic acid production different strains of P. palmata were grown at 5, 10, and 15°C with or without added nitrate. No effect on production was observed, suggesting that the growth conditions in these experiments do not affect the level of gene expression in the pathway of kainic acid biosynthesis. Furthermore, changing the growth conditions did not induce synthesis of kainic acid in the non‐producing strains of Palmariales. © 1994 wiley‐Liss, Inc.