Equilibria between Horseradish Peroxidase and Aromatic Donors.

Cobalt-substituted horseradish peroxidase.

Horseradish peroxidase can be reconstituted with cobalt porphyrin to give a cobaltic holoenzyme having physicochemical properties quite similar to those of the native ferric protein. The cobaltic protein (Co3+HRP) can be reduced to the cobaltous form (CoHRP), the analogue of ferroperoxidase and the reduced cobalt protein can bind O2 to form an analogue of oxyferroperoxidase (Compound III). Sinc...

Stoichiometry of the reaction between horseradish peroxidase and p-cresol.

Over a wide range of pH horseradish peroxidase compound I can be reduced quantitatively via compound II to the native enzyme by only 1 molar equivalent of p-cresol. Since 2 molar equivalents of electrons are required for the single turnover of the enzymatic cycle, p-cresol behaves as a 2-electron reductant. With p-cresol and compound I in a 1:1 ratio compound II and p-methylphenoxy radicals are...

Binding Interactions between Plant-Based Phenolic Chemicals and Horseradish Peroxidase

Horseradish peroxidase (HRP) has the potential to help remediate environmental settings that are contaminated with an array of persistent pollutants. This study investigated chemical interactions between HRP and plant-based phenolic chemicals (PBPCs). The average binding distance between the substrate phenolic hydrogen and the imidazole delta nitrogen (N) of HIS42 was 8.46 Å but this binding d...

Studies on Horseradish Peroxidase

The kinetics of the oxidation of p-cresol by Compound II of horseradish peroxidase has been studied by the stopped flow technique at an ionic strength of 0.11 from pH 2 to 11. In acid solution the reaction is kinetically first order in jcresol, but in the alkaline region a saturation effect attributable to complex formation is observed. At very high pH an additional second order reaction betwee...

The role of protein and porphyrin in the reactivity of horseradish peroxidase toward hydrogen donors.