Question

Why did the reaction rate for enzyme j drop when the temperature exceeded 50 c?

Answer 1

The reaction rate dropped because THE OPTIMUM TEMPERATURE OF THE ENZYME HAS BEEN EXCEEDED.
Each enzyme has the specific temperature and other conditions at which they act best, this is called their optimum condition. When the condition in a reacting system is below or above the optimum conditions of an enzyme, the activity of the enzyme will be reduced.<span />