Competitive Inhibition
If a reversible inhibitor can bind to the enzyme active site in place
of the substrate, it is described as a "competitive inhibitor." In pure competitive
inhibition, the inhibitor is assumed to bind to the free enzyme but not to the
enzyme-substrate (ES) complex. The binding is described as shown below:
![[binding]](images/schem_01.jpg)
Here Ki is the dissociation constant for the EI complex. EI does not
react to form
E + P, and the enzyme is unable to bind both S and I at the same time.
There are several graphical methods for detecting and analyzing
competitive inhibition.
The Michaelis-Menten, Lineweaver-Burk, and Hanes-Woolf equations can all be modified to
include a term that describes the inhibition by I. Choose one of the cases below to
consider each of these in more detail:
The Michaelis-Menten equation
for competitive inhibition is:
The Lineweaver-Burk equation
for competitive inhibition is:
The Hanes-Woolf equation
for competitive inhibition is:
