28.1.111 MixedModelInhib


y=\frac{\frac{V_{\text{max}}x}{1+I_c/(Alpha \cdot K_i)}}{x+\frac{K_m(1+I_c/K_i)}{1+I_c/(Alpha \cdot K_i)}}

Brief Description

A general equation including competitive, uncompetitive and noncompetitive inhibition as special cases.

Sample Curve

CFF MixedModelInhib.png


Number: 5

Names: Vmax, Km, Ki, Alpha, Ic

Meanings: Vmax = Maximum enzyme velocity, Km = Michaelis-Menten constant, Ki = Inhibition constant, Alpha = Constant that determines mechanism, Ic = Inhibitor concentration constant

Lower Bounds: Vmax > 0.0, Km > 0.0, Ki > 0.0, Alpha > 0.0

Upper Bounds: none

Note: This fitting function is for global fitting. When using it, Vmax, Km, Ki, and Alpha are shared, while Ic is a fixed constant.

If Alpha=1, the mixed model is same as a noncompetitive inhibition model. If Alpha is very large, the mixed model is similar to a competitive inhibition model. If Alpha is very small, the mixed model is similar to an uncompetitive inhibition model.

Script Access


Function File



Enzyme Kinetics