Electrochemistry of Chemically Trapped

Native horseradish peroxidase (nHRP) exists in the aggre-gated form in concentrated water solutions as shown by dy-namic light scattering (DLS). This is in contrast to recombi-nant horseradish peroxidase (recHRP) which mainly exists as a dimer. The native enzyme aggregates could be broken into the particles of nm-size only under the conditions of high ionic strength (0.5-1 M NaCl). Chemical cross-linking of recHRP with glutaraldehyde in water solutions yields 40% of the dimer. The chemically trapped dimeric and monomer-ic forms of recHRP were separated by gel-filtration, their substrate specificity towards a number of organic substrates compared. Parameters of direct and mediated electron trans-fer on graphite electrodes catalyzed by both preparations were analyzed. The difference in behavior of the monomeri