Characterization of a novel triphosphonooctaosylceramide from the eggs of the sea hare, Aplysia kurodai

We have reported the existence of a triphosphonoglycosphingolipid, EGL-I, in the eggs of a sea gastropod, Aplysia kurodai [Yamada, S., Araki, S., Abe, S., Kon, K., Ando, S., and Satake, M. (1995) J. Biochem. 117, 794-799]. We have now isolated a novel glycosphingolipid, named EGL-II, from the eggs of Aplysia. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, secondary ion mass spectrometry, and proton magnetic resonance spectrometry, its structure was revealed to be as follows: Galalpha1-->3(GlcNAcalpha1-->2)Galalpha1-->3(3-O-MeGalalpha1-->2)Galalpha1-->3[6'-O-(2-aminoethylphosphonyl)Galalpha1-->2](2-aminoethylphosphonyl-->6)Galbeta1-->4(2-aminoethylphosphonyl-->6)Glcbeta1-->1ceramide. The major aliphatic components of the ceramide are palmitic acid, stearic acid, and anteisononadeca-4-sphingenine.