Explain how a competitive inhibitor changes enzyme kinetics and why adding substrate can reduce its effect.

### What a good answer covers - A competitive inhibitor competes with substrate for enzyme binding. - The inhibition reduces substrate binding at a given substrate concentration. - Apparent $K_m$ increases, while $V_{max}$ is unchanged in the simple model. - Raising substrate concentration can outcompete the inhibitor. ### The concept The Michaelis constant is the substrate concentration at which the reaction rate is half of maximum in the Michaelis–Menten model. A larger apparent value means more substrate is needed to reach that rate. This is why competitive inhibition is described as surmountable by high substrate concentrations, unlike inhibition that removes active enzyme capacity. ### Terms - **Michaelis–Menten model**: a model describing how reaction velocity depends on substrate concentration. - **$V_{max}$**: the maximum reaction velocity under the stated conditions.