Question

A simple mechanism for enzyme-catalyzed reaction is given by the following set of equations:
$\underset{\left(enzyme\right)}{E}+\underset{\left(reactant\right)}{S}\rightleftharpoons \underset{(intermediate-1)}{ES}$
$\underset{(intermediate-1)}{ES}\rightleftharpoons \underset{(intermediate-2)}{EP}$
$\underset{(intermediate-2)}{EP}\rightleftharpoons \underset{\left(enzyme\right)}{E}+\underset{\left(product\right)}{P}$
This is known as the Michaelis-Menten mechanism. The potential energy diagram is shown in the figure. Which of the following sets of identifications is correct? (Assume that the temperature and pressure are constant).

• A. (1) - E + P, (2) - EP, (3) - ES, (4) - E + S
• B. (1) - ES, (2) - Activated complex, (3) - EP, (4) - Activated complex
• C. (1) - EP, (2) - Activated complex, (3) - ES, (4) - Activated complex
• D. (1) - E + S, (2) - ES, (3) - EP, (4) - E + P

Answer 1

The correct option is D (1) - E + S, (2) - ES, (3) - EP, (4) - E + P

(1) represents enzyme (E) and substrate (S),

(2) represents enzyme-substrate intermediate 1 (ES).

(3) represents enzyme product intermediate 2 (EP).

(4) represents enzyme (E) and product (P).

So, option D is correct.