Residual activity of α-galactosidase A in Fabry's disease

Abstract
The α-galactosidase A activity from fibroblasts of five Fabry patients and five controls has been separated from α-galactosidase B through small DEAE-cellulose columns and in some experiments by treatment of the fibroblast extracts with Sepharose coupled to anti-α-galactosidase B antibodies. By these independent methods, it has been shown that there is a residual α-galactosidase A in Fabry's disease, which is immunologically similar to the α-galactosidase A from the controls. The α-galactosidase A from all of the patients and controls has the same apparent Km value for the synthetic substrate 4-methylumbelliferyl-α-galactoside. Four out of five patients have a thermostable α-galactosidase A, while the fifth has a thermolabile enzyme like that from the controls. The amount of immunologically active α-galactosidase A seems to be decreased in the patients tested.