Kinetics and mechanism of catalase action. Formation of the intermediate complex

E. Zidoni*, M. L. Kremer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The kinetics of formation of the intermediate complex between catalase and H2O2 has been reexamined. It has been shown that the kinetics consists of a rapid and of a subsequent slow phase. At the maximum of the transient decrement of the optical absorption, the system was found to be in a terminal state with regard to the rapid phase. On this basis, the formation curve of the intermediate complex was calculated. From the parameters of the curve the maximal saturation of catalase hematins (from horse erythrocytes) by H2O2 is 35%. The absolute spectrum of the intermediate complex was established. The variation of the previously calculated rate constant of formation of the intermediate complex was shown to be due to the inapplicability of the pre-steady-state approximation to the rate data. By applying a more general approach and by the use of a computer, the individual rate constants of the peroxidatic scheme were calculated (relevant to micromolar solutions of catalase) k1 = (3.0 ± 0.2) × 106 M-1 sec-1k4 = (5.6 ± 0.3) × 106 M-1 sec-1 These values are 2.2 times higher in a nanomolar solution.

Original languageEnglish
Pages (from-to)658-664
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume161
Issue number2
DOIs
StatePublished - Apr 1974

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