In a certain enzyme-catalyzed reaction the following steps occur: 1. A phosphate group on substrate A is transferred to a side chain of an active
Site residue of the enzyme.
2. The dephosphorylated form of substrate A dissociates from the enzyme.
3. Substrate B enters the active site and is phosphorylated with simultaneous
Regeneration of the enzyme in its original form.
What kind of kinetic mechanism is described?
A)Random.
B)Sequential.
C)Ordered.
D)Ping-pong.

Question

Quizplus · Accepted Answer

The given mechanism involves substrate A transferring a phosphate group to the enzyme residue, leading to its dissociation and then substrate B entering the active site for phosphorylation. This suggests that the enzyme has two distinct binding sites - one for each substrate. As a result, this mechanism is consistent with the ping-pong kinetic mechanism, where two substrates bind and change the conformation of the enzyme, leading to the release of one product before the binding of the second substrate.

In a Certain Enzyme-Catalyzed Reaction the Following Steps Occur: 1