Question

$K_m$ value of enzyme is substrate concentration at

• A. $1/4V_{max}$
• B. $2V_{max}$
• C. $1/2V_{max}$
• D. $4V_{max}$

Answer 1

The correct option is C $1/2V_{max}$

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 C.