Hemicentrotus pulcherrimus1

Glucosylceramide (Glc/91-lCer) and a novel ceramide trihexoside (Gal£l-6Gal£l-6Glc£l-lCer) were purified from the eggs of the sea urchin, Hemicentrotus pulcherrimus. Their chemical structures were determined by gas-liquid chromatography, methylation analy-sis, chromic acid oxidation, enzymatic hydrolysis, enzyme-linked immunosorbent assay, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The ceramide trihexoside has a novel carbohydrate structure, and its core structure, Gal/?l-6Glc, is also novel. The ceramide moieties of these glycolipids are almost identical. Two fatty acids, 22:1 and 22h:l, constitute more than 80 % of the total acids. Long-chain bases are all phytosphingosine, approximately 90 % of which is n-tl8:0. The finding of melibiosylceramide (Galal-6Glc£l-lCer) from the eggs of another sea urchin species [Kubo, H. et al. (1988) J. Biochem. 104,765-760] and the present finding of the novel ceramide trihexoside suggest that there are a variety of unique sugar structures in sea urchin glycosphingolipids. Eggs of the sea urchin, Anthocidaris crassispina, contain ghicosylceramide and a novel neutral glycosphingolipid