Sulforhodamine GM1-ganglioside: synthesis and physicochemical properties

A fluorescent derivative of GM1-ganglioside was synthesized by linking sulforhodamine 101 to the sphingosine moiety through amino dodecanoyl residue. The product (SR-12GM1) was quantitatively converted to SR-12GM2 by treatment with bovine testes beta-galactosidase and in intact cultured human skin fibroblasts was catabolized to sulforhodamine GM2, GM3 and ceramide; the latter product was further converted to sphingomyelin. In aqueous medium SR-12GM1 formed micelles. When transfer from micelles to vesicles and between vesicles was compared with that of pyrene-GM1, the transfer of SR-12GM1 occurred at higher rates, following in both cases a biexponential curve.