Structural analysis by mass spectrometry of the major mammalian retinal ganglioside, a sialyl-sialyl-dihexosyl-ceramide.

The major mammalian retinal ganglioside was analysed by mass spectrometry. Three types of derivatives were used, the fully methylated, the methylated and reduced and the methylated, reduced and trimethylsilylated compound. The mass spectra unambiguously showed the ganglioside to be a sialyl-sialyl-dihexosyl-ceramide. This is the first conclusive proof that the two N-acetylneuraminic acids are bound to each other constituting the terminal disaccharide. The major species contained sphingosine and stearic acid.