Effects of Single Mutations on the Stability of Horseradish Peroxidase to Hydrogen Peroxide.

Horseradish Peroxidase (HRP) is a commonly used enzyme in many biotechnological fields. Improvement of HRP stability would further increase its potential application range. In the present study, thirteen single- and three double- mutants of solvent exposed, proximal lysine and glutamic acid residues were analysed for enhanced H2O2 stability. Additionally, five single- and one pentuple-consensus mutants were investigated. Most mutants displayed little or no alteration in H2O2 stability; however, three (K232N, K241F and T110V) exhibit significantly increased H2O2 tolerances of 25- (T110V), 18- (K232N), and 12- fold (K241F). This improved stability may be due to an altered enzyme-H2O2 catalysis pathway or to removal of potentially oxidisable residues

Horseradish and Soybean Peroxidases: Comparable Tools for Alternative Niches?

Horseradish and soybean peroxidases (HRP and SBP, respectively) are useful biotechnological tools. HRP is often termed the classical plant heme peroxidase, and although it has been studied for decades our understanding has deepened since its cloning and subsequent expression, which has enabled numerous mutational and protein engineering studies. SBP, however, has been neglected until recently; despite offering a real alternative to HRP that actually outperforms it in terms of stability. SBP is now used in numerous biotechnological applications, including biosensors. Review of both is timely. This article summarises and discusses the main insights into the structure and mechanism of HRP, with special emphasis on HRP mutagenesis, and outlines its use in a variety of applications. It also reviews current knowledge and applications to date of SBP, particularly biosensors. The final paragraphs speculate on the future of plant heme-based peroxidases, with probable trends outlined and explored