Fructose as a carbohydrate constituent of fertilizin from the sand-dollar, Echinarachnius parma.

FERTILIZIN, the sperm-agglutinating substance derived from the jelly-coat of the egg, has been regarded as playing a significant part in the fertilization process in a variety of animals1,2. Studies2–4 of the chemical properties of fertilizin have shown that it belongs to that category of amino-acid- and sugar-containing substances termed glycoproteins or muco-polysaccharides. Many of the constituent amino-acids and sugars have been identified2,5–9 in several species of echinoids. With regard to the carbohydrate components, galactose has been found in Strongylocentrotus purpuratus5,6 and in Echinus esculentus8, fucose in Echinocardium cordatum8, and both these sugars in S. draebachiensis and Paracentrotus lividus8. While not implying that sugar composition is the main basis for the specificity of the fertilizin reaction, we wish to report the presence of fructose as the main monosaccharide derived from the egg-water of the sand-dollar, Echinarachnius parma.