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Cancer-associated serum galactosyltransferase activity. Demonstration in an animal model system
The Journal of Biological Chemistry
|March 10, 1977
Summary
A distinct serum enzyme, galactosyltransferase (GT-IIH), appears and increases with tumor growth in hamsters. This enzyme originates from tumors, unlike the normal serum form (GT-IH), indicating its potential as a tumor biomarker.
Area of Science:
- Biochemistry
- Oncology
- Enzymology
Background:
- Solid tumors were induced in hamsters using polyoma-transformed BHK cells.
- Tumor growth correlated with a unique electrophoretic peak of galactosyltransferase activity in serum.
Purpose of the Study:
- To characterize the electrophoretically distinct galactosyltransferase activity (GT-IIH) associated with tumor growth.
- To compare the properties of tumor-associated GT-IIH with the major serum form (GT-IH).
Main Methods:
- Subcutaneous tumor induction in hamsters.
- Electrophoretic analysis of serum, tumor, and liver enzyme activity.
- Kinetic analysis (Km UDP-galactose) of different enzyme forms.
Main Results:
- A slow-migrating galactosyltransferase (GT-IIH) appeared in serum before tumors were visible and increased with tumor size.
- GT-IIH activity was detected in tumors but not in liver, distinguishing it from the faster-migrating GT-IH found in normal serum and liver.
- GT-IIH exhibited a lower Km for UDP-galactose compared to GT-IH.
Conclusions:
- The study identified a tumor-specific electrophoretic variant of galactosyltransferase (GT-IIH) in hamster serum.
- GT-IIH shows potential as a biomarker for early tumor detection and monitoring of tumor growth.
- Differences in kinetic properties suggest distinct functional roles for GT-IH and GT-IIH.