Question

1. Which of the following would decrease the rate of an enzyme-catalyzed reaction?

Answer 1

Answer:

B) Decrease the cofactor concentration and decrease the enzyme concentration

Explanation:

Different factors affect the rate of enzymatic action.

COFACTOR CONCENTRATION:

All enzymes are proteins. Some enzymes are composed solely of proteins whereas others have an additional component. The protein part in such enzymes is called Apoenzyme and the non-protein part as Cofactor. In such enzymes, the combined apoenzyme and cofactor complex possesses the catalytic activity.

Increasing the cofactor concentration will result in formation of greater number of functional structures, therefore increasing the rate of reaction. Conversely decreasing the cofactor concentration will result in lesser functional units and slower reaction rates.

ENZYME CONCENTRATION:

Increasing the enzyme concentration increases reaction rate provided temperature and pH are kept constant. Conversely decreasing enzyme concentration will decrease the rate of chemical reaction.

INHIBITORS:

The substances which become a barrier in the enzymatic action or inhibit enzymatic action are called inhibitors.

Increasing inhibitor concentration will decrease the reaction rate and decreasing the inhibitor concentration will increase the reaction rate.

Coming back to the answer choices,

B) Decrease the cofactor concentration and decrease the enzyme concentration.

It is the correct answer choice as decreasing enzyme and cofactor concentration will result in decreased functional units and decreased reaction rate.

Answer 2

It would be B. If it was increased it would be “Increase the substrate concentration and increase the enzyme concentration”