Question

Regarding catalytic cycle of an enzyme action, select the correct sequential steps:

1. Substrate enzyme complex formation.
2. Free enzyme ready to bind with another substrate.
3. Release of products.
4. Chemical bonds of the substrate broken.
5. Substrate binding to active site.

Choose the correct answer from the options given below:

Options

• B, A, C, D, E

• E, D, C, B, A

• E, A, D, C, B

• A, E, B, D, C

Answer 1

E, A, D, C, B

Explanation:

The following steps can be used to characterise the catalytic cycle of an enzyme action:

• The substrate first fits into the enzyme’s active site by binding to it (E).
• The substrate creates an “ES” complex by diffusing in the direction of the “active site” (A).
• The enzyme changes shape in response to the substrate binding, fitting the substrate more tightly.
• The new enzyme-product complex is created when the enzyme’s active site, which is now in close proximity to the substrate, breaks the substrate’s chemical bonds (D).
• After releasing the reaction’s products (C), the liberated enzyme is prepared to attach to another substrate molecule (B) and repeat the catalytic cycle.