Substrate specificity of the Chamaerops excelsa palm tree peroxidase. A steady-state kinetic study

Abstract

The steady state kinetic mechanism of the H2O2-supported oxidation of different organic substrates by peroxidase from leaves of Chamaerops excelsa palm trees (CEP) has been investigated. An analysis of the initial rates vs. H2O2 and reducing substrate concentrations is consistent with a substrate-inhibited Ping-Pong Bi Bi reaction mechanism. The phenomenological approach expresses the peroxidase Ping-Pong mechanism in the form of the Michaelis–Menten equation and leads to an interpretation of the effects in terms of the kinetic parameters K(H2O2, m), K(AH2, m), k(cat), K(H2O2, SI), K(AH2, SI) and of the microscopic rate constants k1 and k3 of the shared three-step catalytic cycle of peroxidases. ; Funding from Consejeria de Educación (projects SA129A07 and SA052A10-2) and Consejeria de Agricultura y Ganaderia (Project SA06000) of the Regional Government of Castilla and León (Junta de Castilla y León, Spain) is acknowledged. ; Peer reviewed