Question

What is exhibited by lower $Km$ value?

• A. More affinity with substrate
• B. Less affinity with substrate
• C. More affinity with product
• D. Less affinity with product

Answer 1

The correct option is A More affinity with substrate

k${}_m$ value or Michaelis constant is defined as the substrate concentration at which half of the enzyme molecules are forming (ES) complex or 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 characterizing the different enzymes. A smaller k${}_m$ 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 A.