Lactonization of GD1b ganglioside under acidic conditions.
Gangliosides that contain the disialosyl residue alpha-Neu5Ac-(2--8)-alpha-Neu5Ac-(2--3)- can lactonize in the presence of traces of acid and this reaction has been studied in detail on GD1b [beta-Gal-(1--3)-beta-GalNAc-(1 --4)-[alpha-Neu5Ac-(2--8)-alpha-Neu5Ac-(2 --3)]-beta-Gal-(1--4)-beta-Glc-1--1)-Cer]. Lactonization occurs rapidly at a proton-ganglioside molar ratio of less than 1. At equilibrium, the ratio of GD1b to its lactone is 3:7. The data suggest the possibility that a proton-driven lactonization of gangliosides may occur in vivo.
Bassi
R
R
Department of Medical Chemistry and Biochemistry, Medical School, University of Milan, Italy.
Riboni
L
L
Sonnino
S
S
Tettamanti
G
G
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002855:Chromatography, Thin Layer; D005732:Gangliosides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007783:Lactones / Q000378:metabolism*; D010084:Oxidation-Reduction
D005732:Gangliosides; D007783:Lactones; C033851:ganglioside, GD1b; C059365:ganglioside, GD1b-lactone