Enzyme cofactors such as NAD⁺ function mainly by:

Correct option is C

The correct answer is: (c) lowering the activation energy by stabilising the transition state

Explanation:

• Enzyme cofactors like NAD⁺ (Nicotinamide adenine dinucleotide) play a key role in enzyme catalysis by assisting in the catalytic process.

• They mainly lower the activation energy of reactions by stabilizing the transition state, which makes it easier for the enzyme to facilitate the conversion of substrates into products.

• NAD⁺ acts as an electron carrier in oxidation-reduction reactions, playing a crucial role in many metabolic pathways like cellular respiration.

Information Booster:

• Cofactors are non-protein molecules that are essential for the activity of many enzymes.

• NAD⁺ (and its reduced form NADH) are involved in redox reactions, where they accept or donate electrons, helping in the transfer of energy during metabolic reactions.

• The transition state stabilization is a key mechanism by which enzymes lower activation energy, enhancing the rate of biochemical reactions.

Additional Information:

• Increased enzyme concentration or binding sites for competitive inhibitors are not the primary functions of cofactors like NAD⁺.

• Cofactors may not always be permanent structural components of the enzyme; in fact, they often bind temporarily during the reaction cycle.