Km is the substrate concentration at which

  1. the rate is Vmax
  2. the enzyme denatures
  3. the rate is half of Vmax
  4. the rate is zero
Answer

C) the rate is half of Vmax

Definition of the Michaelis–Menten constant. AS & A Level Biology · Topic 3 Enzymes · 3.2 Factors that affect enzyme action

Biology MCQ · More A Level Biology: Enzymes MCQs · Practise