Biochemistry : Mixed Inhibition

Example Questions

Example Question #1 : Mixed Inhibition

A mixed inhibitor was found to bind unequally to an enzyme and its enzyme-substrate complex. It has a  of  for the enzyme, and a  of  for the enzyme-substrate complex.

If the inhibitor decreased  by a factor of 3, what concentration of enzyme was used?

The answer cannot be determined without knowing the change in the enzyme's

Explanation:

Recall that the change in  is only effected by the binding affinity to the enzyme substrate complex. We can represent the effect on the  by this inhibitor by the following equation.

Since the apparent  decreased by a factor of 3, we know that  is 3.

Solve for  in the following equation:

Above,  is of the enzyme substrate complex, which is

Solve.