Neoglycolipids derived from phosphatidylethanolamine serve as probes in cell culture studies on glycolipid metabolism.
The neoglycolipid (NeoGL) N-acetyl-1-deoxy-1-phosphatidylethanolamino lacto-N-tetraositol [Lc4Ose-PtdEtn(NAc)] and the radioactivly labeled analog [Lc4Ose-PtdEtn(N[14C]Ac)] were synthesized by coupling the corresponding oligosaccharide to phosphatidylethanolamine (dihexadecyl) via reductive amination and subsequent N-acetylation with unlabeled and [14C]acetic acid anhydride, respectively. Lc4Ose-PtdEtn(N[14C]Ac) was then incubated with homogenates of rat small intestine epithelial cells (IEC-6) at pH 4. The reaction products were shown to be the degradation products formed by glycosidases by fast atom bombardment mass spectrometry (FAB MS). On the other hand, incubation of Lc4Ose-PtdEtn(NAc) with IEC-6 cell homogenates in sialyltransferase assays yielded the corresponding sialylated product. When Lc4Ose-PtdEtn(N[14C]Ac) was fed to IEC-6 cells as BSA complex, up to 5% of the NeoGL administered were taken up by the cells. After extraction of the NeoGL and separation by thin layer chromatography (TLC) the catabolic products Lc3Ose-PtdEtn(N[14C]Ac), Lac-PtdEtn(N[14C]Ac), and Glc-PtdEtn(N[14C]Ac), as well as the main anabolic product NeuGc-Lc4Ose-PtdEtn(N[14C]Ac) could be identified by FAB MS. These results demonstrate that PtdEtn-derived NeoGL can be used as probes for studies on the metabolism of specific oligosaccharide structures in cell culture.
Pohlentz
G
G
Institut für Physiologische Chemie, Universität Bonn, Germany.
Drees
B
B
D000818:Animals; D002460:Cell Line; D002855:Chromatography, Thin Layer; D006017:Glycolipids / Q000737:chemistry*; D006031:Glycosylation; D015335:Molecular Probes; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D051381:Rats; D016339:Spectrometry, Mass, Fast Atom Bombardment
D006017:Glycolipids; D015335:Molecular Probes; D010714:Phosphatidylethanolamines