Novel gangliosides of frog brain. Establishment of the structures by their 1H n.m.r. and mass spectra

Abstract

The structures of three gangliosides isolated from bull frog (Rang catesbeiana) brain tissue have been established as disialosylgangliotetraosylceramide (III⁶NeuAcIV³NeuAc-GgOse₄Cer), trisialosylgangliotetraosylceramide [III⁶NeuAcIV³(NeuAc)₂-GgOse₄Cer], and tetrasialosylgangliotetraosylceramide [III⁶(NeuAc)₂IV³(NeuAc)₂-GgOse₄Cer] by ¹H n.m.r. and mass spectral measurements as well as by chemical methods. Although the carbohydrate entity in disialosylgangliotetraosylceramide was identical with that of a ganglioside G_D1α isolated from rat ascites hepatoma AH7974F cells, the ceramide composition of the former clearly differed from that of the latter. A similar distribution of these gangliosides was seen among hemisph, diencephalon, and a mixed tissue of opticlobe, cerebellum, and medulla oblongata of the brain. The brain tissues of Rana nigromaculata and Rhacophorus arboreus also included the same gangliosides as those of bull frog.