Nonlinear oscillatory reaction of catalase induced by gradual entry of substrate.
Characteristic oscillatory reactions were observed when hydrogen peroxide migrated through semipermeable membrane into a solution of catalase. Measurements were made with DO and an mV meter. Oscillation clearly occurred in the range between 25 degrees C and 37 degrees C and between pH 6.0 and pH 7.6. It was also shown that a driving force for the permeation of H2O2, which was the cause of the oscillations, was a deviation from its equilibrium concentration. We made simulations for oscillatory reactions on the basis of these findings. The result indicated that considering the evaporation of O2 was necessary in order to interpret the oscillatory reactions of catalase in addition to the slow entry of substrate caused by deviation from the equilibrium concentration. The fact that oscillations arise by using this method may provide an important insight into the study of enzyme reactions mediated by membranes in living systems, because many enzyme reactions take place with the mediation of a biomembrane.
Hideshima
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Department of Chemistry, Faculty of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263, Japan.
Inoue
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