Factors that Affect Enzyme Activity

FACTORS THAT AFFECT ENZYME ACTIVITY

OVERVIEW

Anything that changes the shape of an enzyme also changes the shape of its active site which determines an enzyme's function.
If the shape of the active site changes then the enzymes ability to function properly is affected and this change can decrease the enzymes enzymatic yield or effectiveness at speeding up chemical reactions.

The Factor of pH

Most enzymes have a pH between 6 to 8 (except pepsin has a pH of 2 and trypsin has a ph of 8)
If the pH of an enzymes changes from its original or optimum pH then it will begin to denature.
- A denatured enzyme loses its normal configuration or shape so it cannot bind to its substrates and this decreases the enzyme's ability to speed up reactions and lowers its reaction rate.

As the pH increases to the optimum point the reaction rate increases.

As the enzyme reaches its optimum pH the reaction rate is at its highest.

As the pH increases past the optimum point the reaction rate decreases as the enzyme denatures.

The Factor of Temperature

The temperature of enzymes CANNOT BE ABOVE 45 degrees Celsius

a) Decreasing the Temperature: An enzyme will slow down its rate of reaction because it will not have enough kinetic energy to pass its minimum activation energy point. HOWEVER, AT LOW TEMPERATURES DENATURING DOES NOT OCCUR!

b) At Optimum Temperatures: The enzyme's reaction rate of reaction and rate of product formation increases since more collisions can occur between the enzyme and the substrate now that the enzyme has enough kinetic energy to pass the activation energy point.

c) Increasing the Temperature Above 45 Degrees Celsius: This will denature the enzyme as bonds will begin to break within the enzyme causing it to change its shape at its active site. When this occurs substrates can no longer bond to the enzyme at its active site and this decreases the enzymes rate of reaction and rate of product formation.

At a low temperature there is less kinetic energy and therefore, a slow reaction rate.

As the temperature rises towards the optimum point the reaction rate does as well since the kinetic energy and number of collisions between substrate molecules increases.

Once temperature increases past the optimum point the enzyme begins to denature and this decreases its reaction rate.

The Factor of the Concentration of Substrates

If the concentration or amount of substrates increases then the amount of product that can be formed also slightly increases.
Since there are more substrates or reactants present in a solution, enzymes are able to react with more substrates molecules and this allows the rate of reaction and product formation to increase.
However, after a certain concentration of substrate the rate will no longer change because the enzymes will become saturated and therefore, cannot work any faster to form products.
Saturation is when all the enzymes present in a solution are all working at their fastest rate. The active sites of these enzymes become full and therefore, the enzyme cannot speed up the reaction nay faster and begins to work at its maximum speed.

The reaction rate increases as the concentration of substrate increases since the enzymes have more substrate molecules to react with.

Eventually the enzymes become saturated and cannot work nay faster to increase the reaction rate. Hence, the reaction rate begins to stabilize, level off and remain constant.

The Factor of the Concentration of Enzymes

The concentration of enzymes limit the overall reaction rate
The more enzymes that are added to a solution the more product that will form. Also, with more enzymes the react of reaction and product formation also increases since there are more places where reactions are occurring simultaneously. As this occurs more product molecules are created.
The rate of reaction NEVER LEVELS OFF, it only continues to increase.

As more enzyme are added the rate of reaction will keep increasing because there more more places where reactions are occurring simultaneously. This increases the rate of product formation and the reaction since more product can be formed in the same frame of time.