Question

Predict each of the folloiwng experimental changes will do to the initial rate of remonal of the phosphate group from Protein X catalyzed by alkaline phosphatase. Answer each with increase decrease or no change and explain biochemically why.

1) change the concentration of phosphatase from 2ug/assay to 4ug/assay

2) increase the pH of the reaction mixture from pH=9 to pH=14

3) Decrease the temperature from 37 degrees C to 4 degrees C

Answer 1

1) Increasing the concentration of enzyme means we are increasing the number of active sites for biochemical reaction. Thus the reaction rate would increase when the concentration of phosphatase increase from 2 ug/assay to 4ug/assay.

2) Increasing the pH from 9 to pH 14 would decrease the rate of phosphate removal by phaosphatase. Higher pH would A possible denaturation of enzyme would create an ineefective reaction medium which would reduce the rate of reaction.

3) Decreasing the temperature from 37 degrees to 4 degrees C would decrease the rate of reaction. It is well known that a 10 degree C increase in temperature doubles the rate of a reaction due to increase in kinetic energy of reacying molecules. So a decrease in temperature reduced the kinetic energy and thus decreases rates of this reaction.