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In a bisubstrate reaction, reactant A binds and is then converted to product C. Next, reactant B binds and is then converted to product D. An experiment showed that B cannot bind without C being released first. What mechanism is indicated by this data?

a) Sequential mechanism
b) Ping-pong mechanism
c) Double-displacement mechanism
d) Competitive inhibition

User Farihah
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1 Answer

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Final answer:

The experiment indicates a b) ping-pong mechanism due to the sequential binding and release of products before the second substrate can bind.

Step-by-step explanation:

In the scenario described where reactant A binds and is converted to product C and subsequently, reactant B can only bind after C has been released, the mechanism that is indicated by this data is the ping-pong mechanism. This type of mechanism is a subset of a bisubstrate reaction known specifically as a double-displacement mechanism. In a ping-pong mechanism, one reactant binds and is released as a product before the second reactant can bind to the enzyme. This contrasts with a sequential mechanism where both substrates would bind before any product is released and is not consistent with competitive inhibition which involves a structure similar to the substrate blocking the active site but not altering the sequence of substrate and product binding.

User Haael
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