Noncompetitive Inhibition
If a reversible inhibitor can bind to the enzyme at a site that is
distinct from the active site,
it is described as a "noncompetitive inhibitor." In pure noncompetitive inhibition,
the inhibitor binds with equal affinity to the free enzyme and to the enzyme-substrate (ES)
complex. The binding is described as shown below:
![[binding]](images/schem_02.jpg)
Here Ki is the dissociation constant for either the EI complex or the IES
complex.
Neither of these complexes can react to form E + P.
There are several graphical methods for detecting and analyzing
noncompetitive 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 noncompetitive inhibition is:
The Lineweaver-Burk equation
for noncompetitive inhibition is:
The Hanes-Woolf equation
for noncompetitive inhibition is:
