Microheterogeneity of arylsulfatase a: Treatment with hydrolytic enzymes

Cerebroside sulfatase also known as arylsulfatase A from human liver displays six microheteromer bands upon narrow pH range isoelectric focusing. Sialic acid residues only partially account for this enzyme multiplicity since neuraminidase treatment reduces the number of bands to three. Uptake studies with cultured fibroblasts strongly suggest arylsulfatase A has covalently bound mannose 6-phosphate residues. However, treatment with alkaline phosphatase and a battery of glycohydrolases failed to reduce the number of enzyme charge forms below three. These results imply that the neuraminidase-resistant charge microheterogeneity is not due to structures associated with the carbohydrate moiety of arylsulfatase A.