Isolation and structure of pulcherrimine, a novel bitter-tasting amino acid, from the sea urchin (Hemicentrotus pulcherrimus) ovaries

A novel sulfur-containing amino acid, pulcherrimine, has been isolated as a bitter principle from ovaries of the sea urchin Hemicentrotus pulcherrimus. The structure was elucidated as 4-(2'-carboxy-2'-hydroxy-ethylthio)-2-piperidinecarboxylic acid by spectroscopic and chemical methods. Absolute stereochemistry was determined by NOE experiments and chiral HPLC analysis. Pulcherrimine exhibited bitterness with a threshold value of 0.306 mM.