The pH range in which an enzyme will remain functional is limited. Within this range there is an optimal pH at which enzyme activity is at its peak. Changes in pH affect the protonation state of an enzyme’s functional groups, altering the intra and intermolecular bonds responsible for the secondary and tertiary structure. This may result in decreased function due to changes at the active site lowering substrate affinity, or full deactivation caused by denaturation (unfolding of the protein).
