TABLE 5

Average parameter estimates (n = 100 repeats) for time-dependent inhibition with non-Michaelis-Menten (enzyme inhibitor inhibitor) inhibition of inactivation (II) kinetics

Data were simulated with the following parameters: II: KI1 = 10 µM, KI2 = 100 µM, kinact1 = 0.025 min−1, kinact2 = 0.0025 min−1, kinact2/KI2 = 2.5 × 10−5 min−1 µM−1.

Model (% Error in Simulated Data)ParameterNumerical MethodaModified (II) Replot MethodaStandard Replot Methoda,b
II (10%)KI18.9–10.90.4–19.60.7–8.9
kinact10.021–0.0310.012–0.0320.011–0.022
kinact24 × 10−10–6 × 10−4NENE
kinact2/KI2 (×10−4)1.8–2.60.0008–1.0NE
II (5%)KI19.3–10.45.1–16.52.7–6.8
kinact10.022–0.0270.018–0.0310.013–0.019
kinact210−7–0.04NENE
kinact2/KI2 (×10−4)1.9–2.30.0007–0.82NE
II (2.5%)KI19.8–10.36.2–13.83.4–5.4
kinact10.024–0.0260.021–0.0290.015–0.018
kinact23 × 10−5–0.026NENE
kinact2/KI2 (×10−4)2.0–2.20.003–1.0NE
  • NE, not estimated.

  • a Data are represented as a range of ±1 S.D. determined from the log normal distribution of 100 runs.

  • b Parameters for the standard replot method are KI and kinact.