Exponential decomposition of H₂O₂ by purified catalase. After the addition of purified erythrocyte catalase (k_cat = 0.033 s⁻¹) at (A) into a solution of H₂O₂ (10⁻⁵ mol/L) the typical exponential decay of H₂O₂ is observed. The addition of 1 mmol/L NaN₃ (B) completely inhibits catalase as shown by a second application of H₂O₂ (C).