Inhibition of Succinic dehydrogenase enzyme by malonate is a classical example of:

The correct answer is Competitive inhibition.

Let's break down the explanation step-by-step:

1. Understanding Enzyme Inhibition:
Enzyme inhibition occurs when a molecule binds to an enzyme and decreases its activity. In competitive inhibition, the inhibitor closely resembles the chemical structure of the enzyme's natural substrate.

2. Analyzing the Specific Case (Succinate Dehydrogenase and Malonate):
Succinate dehydrogenase is an enzyme of the Krebs cycle that catalyzes the oxidation of succinate to fumarate. The chemical structure of malonate (malonic acid) is highly similar to that of the natural substrate, succinate.

3. Mechanism of Competition:
Because of structural similarity, malonate competes with succinate for binding at the active site of succinate dehydrogenase. When malonate binds to the active site, it prevents succinate from binding, thereby inhibiting the enzymatic reaction. This competition can be overcome by increasing the concentration of the substrate (succinate).

4. Conclusion:
Since the inhibitor (malonate) competes directly with the substrate (succinate) for the same active site on the enzyme, this is a classic and well-known example of competitive inhibition.