MICROCALORIMETRY APPLIED TO THE STUDY OF CATALASE REACTION

Microcalorimetry and thermokinetic equations were used to study H2O2 d ecomposition by beef liver catalase. The catalase reaction obeyed the Michaelis-Menten kinetics, and at 298.15 K and pH 7.0, the Michaelis c onstant(K-m), the turnover number and the molar enthalpy(Delta(r)H(m)) of the reaction were 2.36 x 10(-2) mol/L, 1.20 x 10(4) s(-1) and -83. 67 kJ . mol(-1), respectively. The later period of catalase reaction w as a first order reaction for H2O2, and the overall reaction rate cons tant and the first-order rate constant of the reaction were k(o) = 6.3 1 x 10(5) L . mol(-1) . s(-1) and k(1) = 6.31 x 10(5)/[E(0)] s(-1) res pectively. The catalase reaction obeyed Ogura mechanism, and the terna ry complex decomposition rate constant was 6.00 x 10(3) s(-1).