Final answer:
Enzyme inhibitors can reduce or stop the rate of enzyme-catalyzed reactions by binding to enzymes. They exist as irreversible inhibitors, which permanently inactive the enzyme, and reversible inhibitors, which include competitive and noncompetitive types that bind temporarily.
Step-by-step explanation:
Enzyme inhibitors are substances that bind to enzymes and reduce their catalytic activity, effectively decreasing the rate of enzyme-catalyzed reactions. These inhibitors can be classified into two main types: irreversible and reversible.
Irreversible inhibitors bind to an enzyme in such a way that it cannot be removed; the binding is permanent, and the enzyme is permanently inactivated. This is akin to enzyme 'poisoning'.
Reversible inhibitors can bind to enzymes temporarily. There are two subclasses: competitive inhibitors and noncompetitive inhibitors. Competitive inhibitors compete with the substrate for the active site of the enzyme. They can be outcompeted by a high concentration of substrate. Noncompetitive inhibitors, however, bind to a different part of the enzyme and change its shape, which affects enzyme activity even if the substrate concentration is high.
One well-known inhibitor is aspirin, which selectively inhibits an enzyme involved in synthesizing molecules that trigger inflammation.