Electrophoretic analysis of glycoprotein enzymes in the sialidoses and mucolipidoses.

Ten enzymes, all known to be glycoproteins, were examined by electrophoresis or gel isoelectric focusing in 12 different patients with primary or secondary sialidase deficiency. Aberrant electrophoretic mobilities of many of the enzymes attributable to abnormal sialylation were found in all the patients. In ten of the patients seven of the enzymes were affected. The unaffected enzymes were beta-galactosidase, alkaline phosphatase and beta-glucuronidase. In the cells from the two patients with I cell disease (mucolipidosis II) in which sialidase is one of many deficient enzymes, beta-galactosidase, alpha-galactosidase, alpha-fucosidase and alpha-mannosidase were undetectable, alkaline phosphatase showed a normal electrophoretic mobility and acid phosphatase, adenosine deaminase, alpha-glucosidase and beta-D-N-acetylhexosaminidase showed aberrant mobilities.