Efficiency of bovine liver catalase as a catalyst to cleave H2O2 added continually to buffer solutions

Empirical estimations of H2O2 concentration in a system containing bovine liver catalase and continually supplied with H2O2 were done to evaluate the efficiency of the enzyme to cleave H2O2. It was found that the continuous addition of H2O2 leads to the formation of steady-state concentrations of H2O2 in the medium. At a constant catalase concentration both the level and the duration of the steady state are dependent on the flow rate of H2O2. The increase of the catalase concentration in the medium does not change the steady-state level, it merely leads to the maintenance of the steady state for longer durations. At higher flow rates of H2O2, no steady state could be maintained, even when catalase was present in high excess. The incomplete cleavage of H2O2 by catalase under these conditions is due to the low affinity of catalase toward H2O2 (high K m value, apparent K m = 0.1M H2O2) and to the rapid inactivation of the enzyme during the continuous addition of H2O2.