Horseradish peroxidase chemical properties

Wirth, P., Souppe, J., Tritsch, D., and Biellmann, J.F. (1991) Chemical modification of horseradish peroxidase with ethanal-MePEG Solubility in organic solvents, activity and properties. Bioorg. Chem. 19, 133-142. 

In addition to plant and animal sources, peroxidases are also found in mould, bacteria and microorganisms. A peroxidase from the mould Caldariomyces fumago, chloroperoxidase, has been isolated and characterised. Like the plant peroxidases it has ferriprotoporphyrin IX as the prosthetic group. In many of its chemical and physical properties chloroperoxidase is similar to horseradish peroxidase, but it has the unique ability amongst peroxidases to catalyse the oxidation of chloride ion (Hager et al., 1966 Morris and Hager, 1966). 

Ugarova NN, Rozhkova GD, Berezin IV (1979) Chemical modification of the e-amino groups of lysine residues in horseradish peroxidase and its effect on the catalytic properties and thermostability of the enzyme. Biochim Biophys Acta 570 31 12... 

In a more recent series of experiments, George (97) has shown that the secondary hydrogen peroxide complexes of horseradish peroxidase and cytochrome-c peroxidase can be titrated with ferroevanide or ferrous ions and also appear to take part in a one oxidizing equivalent reduction to the ferric form of the enzyme. In this important chemical property they thus resemble the metmyoglobin complex in spite of marked spectroscopic differences in the visible region of the spectrum (Keilin and Hartree, 48). If the peroxide molecule is not a component part of the structure it... 

Engelkamp et al. have reported the incorporation of horseradish peroxidase in the interior cage of CCMV by using its disassembly/assembly property to elucidate a single molecnle stndy of enzyme behaviors (Eig. lid). They showed that CCMV permits easy access of substrates and products through the pores of CCMV and that this permeability can be controlled by pH [58]. These results show that protein nanocages are very nseful templates for the entrapment of functional materials and provide chemical reaction space. 

Prior studies demonstrated that the properties of chemically synthesized polyaniline could be modified by the type of synthesis -electrochemical, chemical, or potential cycling methods (1-5). In addition the optical properties of polyaniline could be controlled by the substituents on the nitrogen or aromatic ring (6,7). Enzyme-catal5rzed polymer syntheses in organic solvents with different amounts of water were described in earlier publications (7-10), and nonlinear optical properties of some of these pol5miers were reported (11). This paper describes the horseradish peroxidase-catalyzed synthesis of polyaniline and the evaluation of its optical properties to determine differences, if any, between this polyaniline and those chemically synthesized. 

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