The abnormalities of beta-galactosidase in GM1-gangliosidoses.

The activity of GM1 beta-galactosidase in the brain and liver of patients with GM1-gangliosidosis was assayed using GM1-ganglioside tritiated in the terminal galactose. In the cases of GM1-gangliosidosis Types 1 and 2A the activity was less than 0.5% of the control. In the liver of GM1-gangliosidosis Type 2B the activity was observed to be much higher than that of Types 1 and 2A. On Sephadex G-150 gel filtration, three active fractions (I, II and III) for 4-methylumbelliferyl beta-galactopyranoside (4MU) and two active fractions (I and II) for GM1-ganglioside were obtained in the control liver. There was no active fraction for GM1-ganglioside in spite of the preserved fraction I for 4MU in the liver of GM1-gangliosidosis Type 1 or Type 2A. In any of the three cases fraction II for both 4MU and G71-ganglioside was not detected.