Multiple choice The catalytic efficiency of two different enzymes can be compared by the pH of optimum value formation of the product Km value molecular size of an enzyme Vmax value Reveal answer Fill a bubble to check yourself C Correct answer Explanation The value of Km (Michaelis-Menten constant) varies from 10-1 to 10-6 M. The catalytic efficiency of two different enzymes can be compared by this value.