Capillary electrophoretic analysis of alkaline phosphatase inhibition by theophylline.


An analytical method for studying enzyme inhibition has been developed using capillary electrophoresis with laser-induced fluorescence detection. This technique is based on electrophoretic mixing of zones of enzyme and inhibitor in substrate-filled capillaries. Enzyme catalytic activity is measured by detecting the fluorescent reaction product as it migrates past the detector. Reversible enzyme inhibition is indicated by a transient decrease in product formation. The enzyme, alkaline phosphatase, has been studied using the fluorogenic substrate AttoPhos ([2,2'-bibenzothiazol]-6-hydroxy-benzthiazole phosphate). This assay has been used to quantify theophylline, a noncompetitive, reversible inhibitor of alkaline phosphatase. The detection limit for theophylline is estimated at 3 microM, and 8.6 amole of alkaline phosphatase are required for each assay. The calculated K(i) for theophylline is 90 microM for the capillary electrophoretic enzyme-inhibitor assays.

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@article{Whisnant2000CapillaryEA, title={Capillary electrophoretic analysis of alkaline phosphatase inhibition by theophylline.}, author={Angela R Whisnant and Susan E Johnston and Stanislava Gilman}, journal={Electrophoresis}, year={2000}, volume={21 7}, pages={1341-8} }