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A high performance liquid chromatography assay for glutamine synthetase
1Molecular Neurobiology Group, Department of Neurophysiology, Neuroinformation Research Institute (NIRI), School of Medicine, University of Kanazawa, Kanazawa, Ishikawa 920, Japan.
Neurochemistry International
|May 28, 2010
Summary
A new high-performance liquid chromatography method accurately measures glutamine synthetase activity by quantifying ?-glutamylhydroxamate. This sensitive assay is applicable to various cell extracts, including neuroblastoma and glioma cells.
Area of Science:
- Biochemistry
- Enzymology
- Neuroscience
Background:
- Glutamine synthetase (GS) is a crucial enzyme in amino acid metabolism and neurotransmitter regulation.
- Accurate measurement of GS activity is vital for understanding cellular function and disease states.
- Existing methods for GS activity assay may lack sensitivity or require complex procedures.
Purpose of the Study:
- To develop and validate a highly sensitive method for quantifying glutamine synthetase activity.
- To establish a reliable assay for ?-glutamylhydroxamate production using high-performance liquid chromatography (HPLC).
- To demonstrate the applicability of the developed method across different biological samples.
Main Methods:
- Utilized high-performance liquid chromatography (HPLC) on an ion-exchange resin column for separation.
- Employed post-column derivatization with o-phthalaldehyde for sensitive detection of ?-glutamylhydroxamate.
- Assayed glutamine synthetase activity in cell-free extracts from fish retina, rat C6 glioma cells, and mouse N18TG2 and NIE 115 neuroblastoma cells.
Main Results:
- The method demonstrated high sensitivity, detecting as little as 50 pmol of ?-glutamylhydroxamate.
- Specific activity of glutamine synthetase varied significantly across different cell types.
- Fish retina exhibited the highest specific activity (1.0 ?mol/30 min/mg protein), followed by rat C6 glioma (0.03), and mouse neuroblastoma cells (0.01).
Conclusions:
- A sensitive and robust HPLC-based method for glutamine synthetase activity assay has been established.
- The method allows for accurate quantification of ?-glutamylhydroxamate, a product of GS activity.
- This assay is suitable for diverse biological samples, facilitating research in neurobiology and enzymology.
