Question

Substrate concentration at which an enzyme attains half its maximum velocity is

• A. Threshold value
• B. Half life
• C. Michaelis-Menten constant
• D. Concentration coefficient

Answer 1

The correct option is C Michaelis-Menten constant

k${}_m$ 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. So, the correct answer is option C.