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Biochemical heterogeneity in I-cell disease. Sucrose-loading test classifies two distinct subtypes
1Department of Pediatrics, Osaka University Hospital, Japan.
Enzyme
|January 1, 1987
Summary
I-cell disease (ICD) shows biochemical heterogeneity. Sucrose loading normalized intracellular hydrolases in some ICD cell lines, revealing two distinct biochemical groups within ICD.
Area of Science:
- Biochemistry
- Cell Biology
- Genetics
Background:
- I-cell disease (ICD) is a lysosomal storage disorder.
- Previous observations showed sucrose normalizing intracellular hydrolases in some ICD cell lines.
Purpose of the Study:
- To investigate the biochemical heterogeneity of I-cell disease (ICD).
- To examine the effects of sucrose loading on lysosomal and Golgi enzymes in ICD fibroblasts.
Main Methods:
- Cultured normal and ICD fibroblasts.
- Assayed intracellular lysosomal enzymes and Golgi enzymes, including N-acetylglucosaminyl phosphotransferase (GlcNAcPTase).
- Measured extracellular hexosaminidase (HEX) activity.
- Applied sucrose loading (88 mmol/l).
Main Results:
- Sucrose loading induced intracellular HEX and GlcNAcPTase activities simultaneously in a subset of ICD cells.
- This response was not observed in all ICD cell lines, indicating heterogeneity.
- Normal fibroblasts did not show the same induced enzyme activities.
Conclusions:
- I-cell disease exhibits significant biochemical heterogeneity.
- Two distinct biochemical groups of ICD exist, differentiated by their response to sucrose loading.
- This heterogeneity impacts intracellular hydrolase activity and enzyme responses.