Ultrasonic and Thermal Inactivation of Catalases from Bovine Liver, the Methylotrophic Yeast Pichia pastoris, and the Fungus Penicillium piceum

The kinetics of inactivation of catalases from bovine liver (CAT), the fungus Penicillium piceum (CAT1), and the methylotrophic yeast Pichia pastoris (CAT2) was studied in phosphate buffer (pH 5.5 or 7.4) at 45 and 50°C or under the conditions of exposure to low-frequency ultrasound (LFUS; 27 kHz, 60 W/cm2). The processes were characterized by effective first-order rate constants (s−1): kin (total inactivation), k in * (thermal inactivation), and k in * (us) (ultrasonic inactivation). The values of kin and k in * increased in the following order: CAT1 CAT > CAT2. Judging from the characteristics of CAT1, it appears to be an optimum component for antioxidant enzyme complexes.