On the mechanism of the peroxidase-catalyzed oxygen-transfer reaction

Abstract

We reported evidence that horseradish peroxidase (HRP) and chloroperoxidase (CPO) catalyze oxygen transfer from H2O2 to thioanisoles [Kobayashi, S., Nakano, M., Goto, T., Kimura, T., & Schaap, A. P. (1986) Biochem. Biophys. Res. Commun. 135, 166-171]. In the present paper, the reaction mechanism of this oxygen transfer is discussed. The oxidation of para-substituted thioanisoles by HRP compound II showed a large negative rho value of -1.46 vs. the sigma + parameter in a Hammett plot. These results are in accord with the formation of a cation radical intermediate in the rate-determining step. Hammett treatments for HRP- and CPO-dependent S-oxygenations did not provide unequivocal proofs to judge the reaction mechanism, because of the poor correlations for sigma + and sigma p parameters. Different behavior was found in kinetics and stereoselectivity between the two enzymes. Results in the present study and recent studies strongly suggested the formation of a cation radical intermediate. The oxygen atom would transfer by reaction of compound II and the cation radical intermediate. Although involvement of the cation radical was not confirmed in the CPO system, a similar mechanism was proposed for CPO.

Chloroperoxidase-catalyzed enantioselective oxidation of methyl phenyl sulfide with dihydroxyfumaric acid/oxygen or ascorbic acid/oxygen as oxidants

“…With H 2 O 2 as oxidant it has been shown previously that the optimum pH for enantioselective sulfide oxidation is 5 Fu et al, 1992;Kobayashi et al, 1987); however, for the DHFA/O 2 and AA/O 2 systems the optimum pH is not known. Therefore, the influence of pH on sulfide conversion and enantiomeric excess of the product was investigated for both systems.…”

“…In addition, CPO catalyzes some P-450-type reactions, such as N-dealkylation of alkylamines (Kedderis et al, 1986), enantioselective epoxidation of styrene and styrene derivatives (Colonna et al, 1993;Ortiz de Montellano et al, 1987), N-oxidation of arylamines (Corbett et al, 1980), and oxidation of organic sulfides. The enantioselective oxidation of sulfides has been investigated by several research groups and seems to take place through a direct transfer of oxygen from compound I to the substrate Colonna et al, 1990Colonna et al, , 1992Doerge, 1986;Kobayashi et al, 1987;Pasta et al, 1994).…”

Characterization of Recombinant Chloroperoxidase, and F103A and C29H/C79H/C87H Mutants

“…(Kobayashi, Nakano et al 1987). It is widely accepted that the formation of Cpd I is the first step for all the reactions that CPO catalyzes (Libby and Rotberg 1990;Green, Dawson et al 2004).…”

“…The dual mechanism of halogenations is proposed to explain the general lack of enantioselectivity during halogenation reactions catalyzed by CPO. Compound X can react with a variety of substrates to perform halogen dependent peroxidatic, catalatic, and peroxygenase reactions (Dunford, Lambeir et al 1987;Kobayashi, Nakano et al 1987;Aaronson, Hager et al 1988;Libby, Rotberg et al 1989). Cpd X can also react with a halogen ion to form molecular halogen.…”

The rational design of semisynthetic peroxidases

“…1.11.1.10) from Caldariomyces fumago, have been shown to catalyze a wide variety of synthetically useful (enantioselective) oxygen transfer reactions with H 2 O 2 (Hager et al, 1998;Van Deurzen et al, 1997a), e.g., asymmetric epoxidation of olefins (Allain et al, 1993;Dexter et al, 1995;Lakner and Hager, 1996), benzylic, propargylic, and allylic hydroxylation (Hu and Hager, 1999;Miller et al, 1995;Zaks and Dodds, 1995), asymmetric sulfoxidation (Colonna et al, 1992(Colonna et al, , 1997Van Deurzen et al, 1997b;Kobayashi et al, 1987), and oxidation of indoles to the corresponding 2-oxindoles (Corbett and Chipko, 1979;Van Deurzen et al, 1996). However, a major shortcoming of all heme-dependent peroxidases, such as CPO, is their low operational stability (Van Deurzen et al, 1997c), resulting from facile oxidative degradation of the porphyrin ring.…”