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Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells
Published on: April 27, 2010
Structures, function, and transformational changes of the sugar chains of glycohormones
1Department of Biochemistry, University of Tokyo, Japan.
Journal of Cellular Biochemistry
|May 1, 1988
Summary
The sugar chains of human chorionic gonadotropin (hCG) differ between normal and malignant conditions. Specific changes in hCG glycosylation can help diagnose trophoblastic diseases like choriocarcinoma.
Area of Science:
- Biochemistry
- Glycobiology
- Hormone Research
Background:
- Human chorionic gonadotropin (hCG) is a protein hormone crucial for pregnancy.
- hCG shares structural similarities with other hormones like luteinizing hormone but has distinct glycosylation patterns.
- The sugar moieties of hCG are complex and vary depending on the source and physiological state.
Purpose of the Study:
- To analyze the oligosaccharide structures of human chorionic gonadotropin (hCG).
- To compare the glycosylation of hCG from normal pregnancy with that from trophoblastic diseases.
- To investigate the functional role of hCG's sugar moiety and its potential as a diagnostic marker.
Main Methods:
- Purification of hCG from urine and placenta.
- Analysis of oligosaccharide composition and structure using biochemical techniques.
- Comparative analysis of hCG glycosylation in normal, hydatidiform mole, choriocarcinoma, and invasive mole patients.
Main Results:
- hCG contains five acidic asparagine-linked sugar chains derived from three neutral oligosaccharides (N-1, N-2, N-3) in a 1:2:1 ratio.
- The alpha- and beta-subunits of hCG have a specific distribution of these oligosaccharides.
- hCG from choriocarcinoma patients contains five additional neutral oligosaccharides not found in normal hCG or hydatidiform mole hCG.
- hCG from invasive mole patients contains a subset of these additional oligosaccharides.
Conclusions:
- The specific distribution of oligosaccharides on hCG subunits provides insights into the functional role of glycosylation.
- Changes in hCG glycosylation, particularly the appearance of tumor-specific sugar chains, are linked to malignant transformation.
- These distinct glycosylation patterns offer potential for developing new diagnostic methods for invasive mole and choriocarcinoma.
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