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Ultramicro enzyme assays in a capillary electrophoretic system
1Department of Chemistry, Purdue University, West Lafayette, IN 47907.
Journal of Chromatography
|September 11, 1992
Summary
This study presents an ultramicro method for enzyme assays using capillary electrophoresis. The technique achieves highly sensitive detection of glucose-6-phosphate dehydrogenase activity, reaching a lower limit of 4.6 x 10(-17) mol.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Biophysics
Background:
- Enzyme assays are crucial for biochemical research and diagnostics.
- Traditional methods may lack sensitivity or require large sample volumes.
- Ultramicro analytical techniques are needed for precise enzyme quantification.
Purpose of the Study:
- To develop and validate an ultramicro method for enzyme assays.
- To determine the activity of glucose-6-phosphate dehydrogenase (G6PD).
- To establish a highly sensitive detection limit for enzyme quantification.
Main Methods:
- Capillary zone electrophoresis (CZE) apparatus with a fused-silica capillary.
- Enzyme (G6PD) injection via electrophoresis or siphoning.
- Electrophoretic mixing of enzyme with substrate, coenzyme, and buffer.
- Detection of product (NADPH) at 340 nm.
- Variable operating potentials, including zero potential for product accumulation.
Main Results:
- Successful separation of enzyme from its product (NADPH) using CZE.
- Product accumulation achieved by manipulating operating potential.
- Quantification of G6PD activity based on product peak height or area.
- Achieved a lower limit of detection of 4.6 x 10(-17) mol for G6PD.
Conclusions:
- The developed ultramicro method enables highly sensitive enzyme assays.
- CZE with controlled potential is effective for enzyme activity determination.
- This method offers a significant advancement in quantifying low enzyme concentrations.