Q18E - Organic Chemistry (Mcmurry)

Question

Look at the following energy diagram for an enzyme-catalyzed reaction:

 

  (a) How many steps are involved?

  (b) Which step is most exergonic? 

  (c) Which step is slowest?

Step-by-Step Solution

Answer

The reaction is two-step.

The fourth step is most exergonic.

The second step is slowest step.

Step 1: Number of steps involved in the reaction

As there are four transition states in the given reaction. Hence reaction is completed in four steps.

Step 2: Exergonic step

The reaction in which energy is released is called an exergonic reaction.

The exergonic reaction has a large negative ${\mathrm{\Delta G}}^{\mathrm{o}}$. If we observe the energy profile diagram carefully then for step 4 the value of ${\text{ΔG}}^{\text{o}}$ is highly negative.

Step 3: The slowest step for the reaction

The rate-determining step is the slowest step in a chemical reaction. Step 2 in which the reaction has high energy is the slowest step.