Mass spectrometric analysis of permethylated glycosphingolipids II. Comparative studies on different blood-group active and related erythrocyte membrane glycosphingolipids.
Three isomeric ceramide tetrasaccharides--P blood-group active globoside, lacto-N-neotetraosyl ceramide as ABH blood-group precursor, both isolated from human erythrocytes and "asialo ganglioside" from human brain as reference standard--and two ceramide pentasaccharides--H blood-group active glycosphingolipid, obtained from blood-group B active ceramide hexasaccharide of human B erythrocytes after alpha-galactosidase treatment and ceramide pentasaccharide from rabbit erythrocytes with B-like blood-group activity--were investigated by mass spectrometry after permethylation. The carbohydrate moiety exhibits differences not only concerning the sugar sequence but also with regard to the position of some glycosidic linkages: Oligosaccharides containing N-acetylhexosamine substituted at position 4 produce spectra that are distinctly different from those containing C-3 substituted N-acetylhexosamines, thus allowing the differentation between type 1 and type 2 carbohydrate chains. Moreover, oligosaccharide ions with a hexose at the cleavage site exhibit a fragmentation pattern different from those with a N-acetylhexosamine at the "reducing terminal". The intensity ratio between parent ion and parent ion -32 mass units is Q greater than or equal to 3 in the first case, whereas in the latter case Q is less than 1. The Q-values are given for 14 oligosaccharide ions. Differences in the composition of the ceramide residues can also be deduced from the mass spectra.
D000017:ABO Blood-Group System; D000818:Animals; D001789:Blood Group Antigens; D002241:Carbohydrates / Q000032:analysis; D002462:Cell Membrane; D002554:Cerebrosides / Q000032:analysis; D004912:Erythrocytes; D005227:Fatty Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006028:Glycosphingolipids / Q000032:analysis*; D006801:Humans; D013058:Mass Spectrometry; D010127:P Blood-Group System; D011817:Rabbits
D000017:ABO Blood-Group System; D001789:Blood Group Antigens; D002241:Carbohydrates; D002554:Cerebrosides; D005227:Fatty Acids; D006028:Glycosphingolipids; D010127:P Blood-Group System