South Eastern Pennsylvania Science Project

This site has been constructed based upon work supported by the National Science Foundation under Grant No. 0230587.

Influence of pH on Enzyme Activity
by Heather Reed

Background information:

Enzymes are critical to the functioning of biological systems.  They help to control the rate at which reactions occur inside the body by either speeding them up or slowing them down.  They are very specific to only one reaction in the organism because of the way the enzyme and the material it is reacting with, referred to as the substrate, fit together.  Once the enzyme and substrate fit together, the reaction takes place, and the enzyme and substrate separate.  The enzyme is not changed or used up in the reaction, and can be reused by the organism. 

Enzymes are very sensitive to changes that take place in their environment.  Changes in temperature and pH can affect the shape of the enzyme, and alter the enzyme’s ability to bind to the substrate and cause a reaction to occur.  At certain temperatures or pH levels, some reactions may not occur.  For each enzyme, there is a range of temperatures and pH levels at which the reaction can occur.

 Enzymes are very sensitive to changes that take place in their environment.  Changes in temperature and pH can affect the shape of the enzyme, and alter the enzyme’s ability to bind to the substrate and cause a reaction to occur.  At certain temperatures or pH levels, some reactions may not occur.  For each enzyme, there is a range of temperatures and pH levels at which the reaction can occur.