Final answer:
The decomposition time of peroxide decreases as enzyme concentration increases until the substrate becomes saturated. Beyond this saturation point, increasing enzyme concentration will not affect the decomposition rate. Option 1 is correct.
Step-by-step explanation:
As enzyme concentration increases, the time it takes for peroxide to decompose generally decreases. This is because more enzyme molecules are available to catalyze the reaction, thereby increasing the rate of reaction.
However, this acceleration will only continue until all substrate molecules (hydrogen peroxide in this case) are bound to enzyme molecules. Once this point, known as the saturation point, is reached, adding more enzymes will not further increase the rate of decomposition.
In your initial non-enzyme-catalyzed study, you observed the rate of decomposition by measuring the concentration changes over time at a constant temperature. Enzyme-catalyzed reactions differ in that they will reach a point where increasing the enzyme concentration no longer affects the rate of reaction.
The optimal conditions for enzyme activity are also important, as very high temperatures or incorrect pH levels can lead to enzyme inactivation.