A student increases the concentration of substrate in a reaction mixture containing a fixed amount of enzyme. What happens to the rate of reaction once all active sites are occupied?

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Question

A student increases the concentration of substrate in a reaction mixture containing a fixed amount of enzyme. What happens to the rate of reaction once all active sites are occupied?

Accepted Answer

The rate levels off and remains constant — When all active sites of available enzyme molecules are occupied (enzyme saturation), adding more substrate cannot increase the rate further. The rate plateaus at the maximum velocity (Vmax) for that enzyme concentration. The rate only drops if an inhibitor or denaturing condition is introduced.

Answer

The rate levels off and remains constant

Answer

The rate increases then decreases

Answer

The rate continues to increase indefinitely

Answer

The rate drops sharply to zero

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