Why was there not a significant difference in the reaction rate with 800 mg of substrate as compared to 400 m. of substrate? What would you need to add to see an increase in the reaction rate with 800 mg of substrate?

A. Concentration of substrate can affect the rate of reaction by two condition given below-

1. At low concentration of substrate, there will be increase in the rate of reaction by increasing the concentration of substrate. There would be catalytic site of enzyme available to bind to substrate.

2. The enzyme becomes saturated with substrate as the substrate concentration increases. At a point when the rate of product formation now depends on the activity or the available active sites of the enzyme itself, so, increasing more substrate will not leads to any effect on the rate of the reaction to any significant level.

Thus, there was not a significant difference in the reaction rate with 800 mg of substrate as compared to 400 m as at 400 mg all the catalytic site or active site are bound already.

B. Increasing the enzyme concentration will lead to increase the rate of reaction at 800 mg as there will be more active sites to bound to substrate.