Abstract
The substrate depletion approach is an increasingly popular alternative to the traditional method (observing product formation) of determining the kinetic parameters (KM and Vmax) of an enzyme. Obach and Reed-Hagen (Drug Metab Dispos 30:831–837, 2002) used an empirical relationship between substrate depletion rate constants and initial substrate concentration to determine kinetic parameters for a number of cytochrome P450-catalyzed reactions. We present a proof that this relationship can be derived from the Michaelis-Menten equation and, therefore, that kinetic parameters obtained by the substrate depletion approach are equivalent and comparable to those obtained by the traditional product formation approach. Analysis of a simulated data set produced similar kinetic parameters regardless of which approach was used, confirming the theoretical result.
Footnotes
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This work was supported by National Institutes of Health Grants GM-32165 and GM-62284.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.106.010777.
- Received April 24, 2006.
- Accepted May 26, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
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