G M1 Gangliosidosis: Enzymatic variation in a single family

Acid β‐galactosidase activity can be separated into multiple molecular forms by isoelectric focusing on cellulose acetate membranes. The residual acid β‐galactosidase in the juvenile form of G M1 gangliosidosis has three bands of enzyme activity with an apparent isoelectric pH (pI) range from 4.9 to 5.2, whereas that in the infantile form has a single band with an apparent isoelectric pI of 5.2. Separation of residual acid β‐galactosidase into multiple molecular forms by analytical isoelectric focusing demonstrates enzymatic differences that can be correlated with the allelic mutations that affect the G M1 ganglioside β‐galactosidase locus.