Croatica Chemica Acta, Vol. 69 No. 3, 1996.
Original scientific paper
Catalytic Intermediates in the Reaction of Deuteroferriheme with m-Chloroperoxybenzoic Acid
Vera Imper
; Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, 10000 Zagreb, Croatia
Harald E. Van Wart
; lnstitute of Biochemistry and Cell Biology, Syntex Discouery Research, 1401 Hilluiew Aue., Palo Alto, CA 94304, USA
Abstract
Deuteroferriheme (DFH) reacts with m-chloroperoxybenzoic acid
(m-CPBA) to produce areaction intermediate whose optical spectrum
resembles that of horseradish peroxidase (HRP) compound o. To exclude problems related to aggregation, the fraction of dimers
was maintained below 2%. Under these conditions, the reaction of
DFH with m-CPB in 10 mM phosphate containing 1% u/u 1,2-dimethoxyethane (I = O.lM NaCI) at pH 5.5 at 1 °C was shown to
produce an intermediate that has a distinctive Soret band near 350
nm, in agreement with earlier observations in the literature. The
EPR spectrum of this intermediate indicates that it contains half ferric iron and cannot be a ferryl dimer. Its structure is more consistent with that of a ferric, ferryl dimer and a scheme supporting its formation has been proposed.
Keywords
Hrčak ID:
177127
URI
Publication date:
1.11.1996.
Visits: 923 *