I - cell disease ( mucolipidosis 11 ) : resolution of N - acetyl - p - D - glucosaminidase and a - L - fucosidase components by DEAE - cellulose chromatography

1. In a patient with I-cell disease the activities of several acid hydrolases were elevated in plasma and reduced in cultured fibroblasts when compared with normal values. Normal activities for the enzymes were found in leucocytes. These findings agree with reports on other cases. 2. N-Acetyl-8-D-glucosaminidase was resolved into its component forms by chromatography on microcolumns of DEAE-cellulose coupled with continuous automated assay of activity in the column effluent. Cultured skin fibroblasts from three patients showed a profound deficiency of glucosaminidase component A and a relative increase in the activity of a form eluted earlier than A. 3. In the one patient studied, the elution profile of plasma glucosaminidase was similar to that of normal plasma, but treatment with neuraminidase revealed a minor component which did not appear in control specimens. 4. Chromatographic resolution of glucosaminidase secreted by normal fibroblasts into the culture medium showed that component A comprised two forms, a serum-type and a tissue-type, whereas only a serum-type was found in I-cell medium. 5 . Different forms of a-L-fucosidase were shown to occur in normal plasma and fibroblasts. This is the second lysosomal hydrolase for which differences between intracellular and extracellular forms have