How do inhibitors affect the rate of a reaction?

Inhibitors slow down the rate of a reaction by preventing reactants from forming products.

Inhibitors are substances that can decrease the rate of a reaction. They achieve this by interacting with the reactants or the catalysts involved in the reaction, thereby preventing the formation of products. There are two main types of inhibitors: competitive and non-competitive.

Competitive inhibitors work by binding to the active site of an enzyme, the place where the reaction occurs. They have a similar structure to the substrate, the molecule that the enzyme acts upon, and can fit into the active site, blocking it. This means that the substrate cannot bind to the active site, slowing down the reaction rate. The effect of competitive inhibitors can be reduced by increasing the concentration of the substrate. This is because the more substrate there is, the less likely it is that the inhibitor will be in the active site at any one time.

Non-competitive inhibitors, on the other hand, do not compete with the substrate for the active site. Instead, they bind to another part of the enzyme, changing its shape. This makes the active site less effective at catalysing the reaction, or even completely ineffective. Unlike with competitive inhibitors, increasing the substrate concentration does not overcome the effect of non-competitive inhibitors.

Inhibitors play a crucial role in controlling the rate of chemical reactions in various fields, including in our bodies. For example, many drugs work by inhibiting enzymes that cause disease. Understanding how inhibitors affect reaction rates is therefore not only important for your chemistry studies, but also for understanding how medicines work.