pH z Extremes generally inactivate enzymes z pH optimum z Maximum activities between pH 4.5 – 8.0 z Narrow pH range z Exceptions – Pepsin: optimum pH is 1.8 – Trypsin: optimum pH is 9.8pH z Extremes generally inactivate enzymes z pH optimum z Maximum activities between pH 4.5 – 8.0 z Narrow pH range z Exceptions – Pepsin: optimum pH is 1.8 – Trypsin: optimum pH is 9.8