Enzyme Activity: pH and Temperature

Enzyme Activity and pH

• Most enzymes work best at a neutral pH (around 7)
• Enzymes have an optimal pH range where their activity is highest.
• Outside this range, enzyme activity decreases due to changes in the enzyme's shape.
• The shape of the enzyme's active site is affected by pH.
• The substrate may no longer fit into the active site if the pH deviates significantly from the optimum.
• Extreme pH values can permanently denature the enzyme.

Enzyme Activity and Temperature

• Enzymes function optimally within a specific temperature range.
• Enzyme activity increases as temperature increases, up to a point optimal temperature.
• Above the optimal temperature, enzyme activity rapidly decreases.
• High temperatures lead to denaturation of the enzyme's protein structure causing a permanent loss of function.

Optimal pH and Temperature

• Different organisms, like bacteria, in which optimal temperature could vary and which could be adapted to survive and function within extreme environments.
• Mammals and birds, maintaining a constant internal body temperature (homeostasis), their enzymes function optimally near 37°C.
• Enzymes evolved their temperature and pH optima to match their environment.