Enzyme activity is affected by pH because __________.

• A. most substrates do not function well at high or low pH
• B. low pH will denature all enzymes
• C. changes in pH can cause loss of cofactors from the enzyme
• D. the binding of hydrogen ions to the enzyme absorbs energy and thus there may not be enough energy to overcome the activation energy barrier
• E. high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the active site