Correction of the Enzymic Defect in Cultured Fibroblasts from Patients with Fabry's Disease: Treatment with Purified α-Galactosidase from Ficin
The terminal galactosyl residue of ceramide trihexoside of human erythrocytes and BHK fibroblasts and that of the ceramide trihexoside derived from “globoside” of human erythrocytes were hydrolyzed and totally converted to ceramide lactoside by an oc-galactosidase isolated from fig. The enzyme showed a strict substrate specificity for agalactosides and was completely freed from ,&galactosidase activity. With the sequential application of glycosidases, the carbohydrate sequence and anomeric linkages of glycosphingolipids have been simultaneously determined. The presence of cr-anomeric (equatorial) proton in theseglycolipids was supported by a doublet at 6 4.6 ppm (J = 2 Hz) in the nuclear magnetic resonance spectrum of a trimethylsilyl derivative and by an absorption at 850 cm-l in the infrared spectra. From these results and the results of methylation study, the structures of ceramide trihexoside and of globoside were determined, respectively, galactopyranosyl-cr-(1 + 4). galactopyranosyl$(l ---t 4)glucopyranosyl-(1 + l)ceramide, and 2-acetamido-Z-deoxy-galactopyranosyl-P-(1 + 3)galactopyranosyl-ac-(1 + 4)galactopyranosyl-P-(1 --+ 4)glucopyranosyl(1 + 1)ceramide.