Question

A competitive inhibitor of succinic dehydrogenase is?

• A. α-ketoglutarate
• B. Oxaloacetate
• C. Malonate
• D. Malate

Answer 1

The correct option is C

Malonate

The correct option is C.

Explanation of correct option:

1. An inhibitor is a type of chemical compound that renders enzyme activity.
2. A competitive inhibitor shows structural similarity with the substrate and prevents the binding of the substrate to the enzyme.
3. The competitive inhibitor of succinic dehydrogenase is malonate.
4. Malonate closely resembles the substrate succinate and binds to the active site of the enzyme, thereby inhibiting enzyme activity.

Explanation of incorrect option:

Option A:

1. α-ketoglutarate is an intermediate compound of Kreb's cycle.
2. It is converted to succinyl-CoA by the enzyme α-ketoglutarate dehydrogenase.

Option B:

1. Oxaloacetate is an intermediate of Kreb's cycle.
2. It is also involved in gluconeogenesis.

Option D:

Malate is produced in Kreb's cycle, which is converted to oxaloacetate by malate dehydrogenase.

Final answer: A competitive inhibitor of succinic dehydrogenase is malonate.