Multiple molecular forms of arylsulfatase A in different forms of metachromatic leukodystrophy (MLD).

Arylsulfatase A (ARA) can be separated into six to eight individual enzymatic bands of activity by isoelectric focusing on cellulose acetate membranes. The residual ARA activity in juvenile metachromatic leukodystrophy (MLD) has a single band of activity with apI of 5.5, whereas the residual ARA in the late infantile form of MLD has three bands of activity with pI range of from 5.4 to 5.8. The technique of isoelectric focusing on cellulose acetate membranes demonstrates enzymatic differences which can be correlated with the clinical form of the disease.