Integrated Rate Equation Considering Product Inhibition and Its Application to Kinetic Assay of Serum Ethanol
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Kinetic assay of serum ethanol was investigated by predicting maximal product absorbance at 340 nm (<i>A</i><sub>mk</sub>) through fitting to the yeast alcohol dehydrogenase reaction curve with the integrated rate equation, taking into account product inhibition in the presence of semicarbazide. Predicted <i>A</i><sub>mk</sub> linearly responded to the preset constant of steady-state concentration of acetaldehyde (<i>C</i><sub>ald</sub>). An exponential correlation function was established between desired <i>C</i><sub>ald</sub> and putative <i>A</i><sub>mk</sub> for authentic ethanol. For unknown samples, iterative fitting to reaction curve till preset constant <i>C</i><sub>ald</sub> and resultant <i>A</i><sub>mk</sub> satisfied this exponential correlation function yielded <i>A</i><sub>mk</sub> with variation coefficient <4.3%. Variations in enzyme activity, data range and kinetic parameters showed negligible effects. The recovery was consistent to 100% with resistance to methanol and isopropanol. The upper limit of linear response for <i>A</i><sub>mk</sub> was about 40 times of the lower limit. These results indicated that this kinetic method was reliable for serum ethanol assays with obvious advantages.
- Analytical Sciences
Analytical Sciences 23(4), 439-444, 2007-04-10
The Japan Society for Analytical Chemistry