Kinetic analysis of compound I formation and the catalatic activity of chloroperoxidase

Abstract

When the only substrate added to a solution of chloroperoxidase is a hydroperoxide, the reactions are: ferric enzyme + ROOH → compound I + ROH and compound I + ROOH → ferric enzyme + O2 + ROH. When H2O2 is used as substrate, the rate constants for the formation and catalatic decomposition of compound 1 are 2.4 × 106 M−1∙s−1 and 3.4 × 105 M−1∙s−1 at pH 4.7 and it is predicted that a maximum of 87% of the enzyme converts to compound I in the steady state of the catalatic reaction. With methyl hydroperoxide, formation of compound I has a rate constant of 4.7 × 105 M−1∙s−1 and its decomposition 2.9 × 104 M−1∙s−1. When peracetic acid is used, compound I is formed with a rate constant of 3.8 × 106 M−1∙s−1 and a 100% yield of compound I is obtained.