The response of an amperometric biosensor at mixed enzyme kinetics and diffusion limitations was modelled digitally in the case of substrate inhibition. Digital simulations were carried out using a finite difference technique. Calculations showed complex kinetics of biosensor response. At low enzyme activity and substrate concentration (S0), the response of the sensor looks like it is limited by a simple substrate diffusion. At substrate concentration comparable to the Michaelis-Menten constant (KM), the response change shows a maximal value. A sharp response change was indicated at high enzyme activity and high (4.9 > S0/KM > 4.5) substrate concentration. This was explained by multi-concentration of substrate generation inside the enzyme layer. This conclusion was confirmed by the analytical solution of the simplified biosensor model with external diffusion limitation at steady-state conditions. The complex kinetics of response change produces different calibration graphs for biosensor response at transition and steady state.
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机译:在底物抑制的情况下,数字化模拟了安培生物传感器对混合酶动力学和扩散限制的响应。使用有限差分技术进行了数字仿真。计算显示出生物传感器响应的复杂动力学。在低酶活性和底物浓度(S 0 sub>)下,传感器的响应似乎受到简单底物扩散的限制。在底物浓度与米氏常数(K M sub>)相当的情况下,响应变化显示出最大值。在高酶活性和高(4.9> S 0 sub> / K M sub 4.5)底物浓度下,响应变化剧烈。酶层内部多浓度的底物生成可以解释这一点。这个结论被简化的生物传感器模型在稳态条件下具有外部扩散限制的解析解所证实。响应变化的复杂动力学为生物传感器在跃迁和稳态下的响应生成了不同的校准图。
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