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Updated: Aug 4, 2026
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Biochemical Titration of Glycogen In vitro
Published on: November 24, 2013
New and specific nucleoside diphosphate glucose substrates for glycogenin
M D Alonso1, E J Lagzdins, J Lomako
1Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, FL 33101.
FEBS Letters
|February 13, 1995
Summary
Glycogenin uses UDP-glucose for glycogen synthesis. Researchers found it also utilizes pyrimidine nucleotides CDP-glucose and TDP-glucose, with CDP-glucose useful for assaying glycogenin.
Area of Science:
- Biochemistry
- Molecular Biology
- Glycogen Metabolism
Background:
- Glycogenin is the essential primer for glycogen synthesis.
- It is known to be self-glucosylating using UDP-glucose.
- The in vivo substrate specificity of glycogenin is not fully understood.
Purpose of the Study:
- To investigate the substrate specificity of glycogenin beyond UDP-glucose.
- To identify alternative nucleoside diphosphate glucose substrates for glycogenin.
- To explore the potential of alternative substrates for glycogenin assay development.
Main Methods:
- Enzymatic assays were performed using purified glycogenin.
- Glycogenin's ability to utilize various nucleoside diphosphate glucoses was tested.
- Enzyme kinetics were compared between different substrates.
Main Results:
- Glycogenin utilizes UDP-glucose, CDP-glucose, and TDP-glucose.
- Purine nucleotides were not utilized as substrates.
- CDP-glucose was utilized at 70% the rate of UDP-glucose.
- CDP-glucose is not a substrate for glycogen synthase.
Conclusions:
- Glycogenin exhibits broader substrate specificity than previously assumed, including pyrimidine nucleotides.
- CDP-glucose presents a valuable tool for specifically detecting and assaying glycogenin in complex biological samples.
- This finding has implications for understanding glycogen metabolism regulation and developing specific diagnostic tools.
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