Two novel isoneolacto-undecaglycosylceramides carrying Gal alpha 1 -> 3Lewis(x) on the 6-linked antenna and N-acetylneuraminic acid alpha 2 -> 3 or galactose alpha 1 -> 3 on the 3-linked antenna, expressed in porcine kidney

Three sialosylated and three neutral glycosphingolipids sharing a common is o-neolacto core were isolated from porcine kidney cortex. They were purifie d by preparative HPTLC, and were characterized by partial exoglycosidase hy drolysis followed by thin layer chromatography and immunostaining with anti -Gal alpha 1-->3Gal, anti-type 2 lactosamine and anti-Lewis(x) antibodies, methylation analysis, MALDI-TOF mass spectrometry and H-1-NMR spectroscopy. Among neutral glycolipids, one was a known structure, (VIVI)-V-3'(3)(alpha Gal)(2)-iso-nLc(8)Cer, and two were novel structures differing by the numb er of Gal alpha 3Lewis(x) determinants: (VIVI)-V-3'(3)(alpha Gal),V'3 alpha Fuc-iso-nLc(8), and (VIVI)-V-3'(3)(alpha Gal)(2) (VV)-V-3'(3)(alpha Fuc)(2 )-iso-nLc(8). The single Gala3Lewis(x) determinant was found on the 6-linke d antenna. Among sialosylated glycolipids, two had been previously found in other species and tissues, (VIVI)-V-3'(3)(NeuAc)(2)-iso-nLc(8), and VI(3)N euAcVI'(3)alpha Gal-iso-nLc(8). A novel structure was discovered presenting a Gal alpha 3Lewis(x) determinant on the 6-linked antenna and a N-acetylne uraminic acid on the 6-linked antenna, VI(3)NeuAcVI'(3 alpha)GalV'(3)alpha Fuc-iso-nLc(8). These results indicate that, in vivo, the porcine kidney al pha 3fucosyltransferase synthesizes the Gal alpha 3Lewis(x) determinant, ac ting on the 6-linked before the 3-linked Gal alpha 3neolactosamine, and app ears unable to synthesize the sialosylated Lewis(x) determinant on neolacto series glycolipids.