Question

Catalytic efficiency of two different enzymes is compared by their

• A. Product
• B. Molecular size
• C. $K_m$ value
• D. pH optimum value

Answer 1

The correct option is C $K_m$ value

k${}_m$ value or Michaelis constant is defined as the concentration of the substrate when the velocity of the enzyme reaction is half the maximum value. The k${}_m$ varies from enzyme to enzyme and is used in characterising the different enzymes. A smallerk${}_m$ value indicates greater affinity of the enzyme for its substrate, hence, shows a quicker reaction k${}_m$ is a constant characteristic of an enzyme for its conversion of a substrate.

So, the correct answer is option C.