3. Enzymology

Inhibition — Quiz

Test your understanding of inhibition with 5 practice questions.

Practice Questions

Question 1

In a mixed inhibition scenario with $K_i=10\,\mu\mathrm{M}$ and $K_i'=20\,\mu\mathrm{M}$ at inhibitor concentration $[I]=10\,\mu\mathrm{M}$, what are the values of the factors $\alpha$ and $\alpha'$?

Question 2

Which kinetic plot displays 1/velocity ($1/v$) versus inhibitor concentration $[I]$ at fixed substrate levels and is commonly used to determine $K_i$?

Question 3

End-product inhibition of threonine deaminase by isoleucine exemplifies which type of enzyme inhibition and what is its effect on $V_{max}$ and $K_m$?

Question 4

An enzyme has $V_{max}=200\,\mu\mathrm{M/s}$ and $K_m=0.5\,\mathrm{mM}$. In the presence of a competitive inhibitor with $K_i=0.5\,\mathrm{mM}$ at $[I]=0.5\,\mathrm{mM}$ and substrate concentration $[S]=1\,\mathrm{mM}$, what is the reaction rate $v$?

Question 5

Which experimental observation distinguishes pure noncompetitive inhibition from general mixed inhibition when varying inhibitor concentration?