MINI-REVIEW An updated view on horseradish peroxidases: recombinant production and biotechnological applications

peroxidase has been the subject of sci-entific research for centuries. It has been used exhaustively as reporter enzyme in diagnostics and histochemistry and still plays a major role in these applications. Numerous studies have been conducted on the role of horseradish peroxidase in the plant and its catalytic mechanism. However, little prog-ress has been made in its recombinant production. Until now, commercial preparations of horseradish peroxidase are still isolated from plant roots. These preparations are commonly mixtures of various isoenzymes of which only a small fraction has been described so far. The composition of isoenzymes in these mixed isolates is subjected to uncontrollable environ-mental conditions. Nowadays, horseradish peroxidase regains interest due to its broad applicability in the fields of medicine, life sciences, and biotechnology in cancer therapy, biosensor systems, bioremediation, and biocatalysis. These medically and commercially relevant applications, the recent discovery of new natural isoenzymes with different biochemical proper-ties, as well as the challenges in recombinant production ren-der this enzyme particularly interesting for future biotechno-logical solutions. Therefore, we reviewed previous studies as well as current developments with biotechnological emphasis on new applications and the major remaining biotechnological challenge—the efficient recombinant production of horserad-ish peroxidase enzymes