Isoelectric focusing of acid hydrolases in human liver and serum. Findings in sera from one patient with I-cell disease phenotype

Sialic acid residues contribute to the heterogeneity of human serum ribonuclease: demonstration by isoelectric focusing and neuraminidase treatment of serum

Ribonuclease (RNase) activity from human serum appears as multiple zones of activity following isoelectric focusing in thin layer polyacrylamide gel. At least one but not all of these zones is cross reactive with rabbit antibovine pancreatic RNase A antiserum. Treatment of serum or partially purified serum RNase with neuraminidase reduces the complexity of the serum RNase banding pattern to a major band which focuses at a pH of 9.5 or greater and a minor zone of activity which focuses at about pH 6.0-6.2. Trypsin does not affect the pattern. Thus, sialic acid residues account for a large portion of the heterogeneity of human serum RNase. Neuraminidase treatment is requisite for evaluating RNase from serum and certain other sources.

Acid hydrolases in sera and plasma from patients with cystic fibrosis

The enzyme activities of alpha-fucosidase (pH 4.0 and pH 5.5), alpha-galactosidase, beta-galactosidase, alpha-glucosidase (pH 4.5 and pH 6.0), beta-glucosidase, beta-glucuronidase, beta-hexosaminidase, and alpha-mannosidase (pH 4.5 and pH 5.5) were investigated in sera from cystic fibrosis (CF) patients. Several of these activities were significantly increased in sera from patients compared to age-matched control children. CF-patients in a more advanced stage of the disease had a tendency to higher values of some of these hydrolases than those in better condition. No new isoenzymes of these hydrolases were found. Only minor differences could be detected in the pH-profiles of alpha-mannosidase and acid phosphatase from age-matched normal controls, heterozygotes and homozygotes for CF. With our technique, alpha-mannosidase and acid phosphatase showed the same thermostability in CF-patients. CF-heterozygotes and age-matched controls, except at 56 degrees C, when the activity of acid-phosphatase in the plasma from adult CF-heterozygotes decreased more than that from adult controls

Molecular forms of beta-hexosaminidase and alpha-mannosidase in cell cultures from patients with mucolipidosis types II and III

Molecular forms of beta-hexosaminidase and alpha-mannosidase were studied using isoelectric focusing in fibroblasts and culture medium from patients with mucolipidosis Types II and III. Compared to controls, no significant aberrations could be found in the isofocusing isoenzyme pattern. Mannose-6-phosphate, which inhibits the uptake of lysosomal enzymes into the cells, was added to the cell cultures from controls without any significant effect on the isofocusing isoenzyme pattern.

Isoelectric focusing of acid hydrolases in human fibroblasts and leucocytes

Lysosomal hydrolases in fibroblasts and leucocytes exhibited the same isoelectric focusing pattern as found in liver. Treatment with neuraminidase had a great effect on the pattern of several glycosidases while treatment with alkaline phosphatase did not significantly change the pattern. These findings are discussed with special reference to the different "uptake" systems that exist for acid hydrolases.