Oxidation of horseradish peroxidase compound II to compound I.

Oxidation of horseradish peroxidase compound II to compound I.

In the reaction between equimolar amounts of horseradish peroxidase and chlorite, the native enzyme is oxidized directly to Compound II (Hewson, W.D., and Hager, L.P. (1979) J. Biol. Chem. 254, 3175-3181). At acidic pH but not at alkaline values, this initial reaction is followed by oxidation of Compound II to Compound I. The highly pH-dependent chemistry of Compound II can be readily demonstra...

Mechanism of Oxidation by Horseradish Peroxidase Compound

Binding of p-cresol to native horseradish peroxidase was investigated by differential spectrophotometry, and the value lo3 Kdiss = 3 M was obtained at neutral and acid pH; binding is not competitive with that of cyanide and hydroxide. The Soret region spectrum of Compound II of the enzyme was measured in the steady state at pH 4.26, 6.89, and 10.95, and the differences were found to be too smal...

Spectroscopic evidence in support of horseradish peroxidase compound II-catalyzed oxidation of salicylic acid but not of phenylethylamine.

Salicylic acid and phenylethylamine are putative substrates for naturally occurring reactions for generation of reactive oxygen species, which are catalyzed by plant peroxidases. Here, we used commercially available highly purified horseradish peroxidase-C (HRP-C) as a model enzyme for spectroscopic analysis, and obtained data suggesting that the Compound II form of HRP-C does not utilize pheny...

Proton nuclear magnetic resonance investigation of the electronic structure of compound I of horseradish peroxidase.

Chemical nature of the porphyrin pi cation radical in horseradish peroxidase compound I.

The electron paramagnetic resonance (EPR) and Mössbauer properties of native horseradish peroxidase have been compared with those of a synthetic derivative of the enzyme in which a mesohemin residue replaces the natural iron protoporphyrin IX heme prosthetic group. The oxyferryl pi cation radical intermediate, compound I, has been formed from both the native and synthetic enzyme, and the magnet...