title: Magnetic field effects and radical pair mechanisms in enzymes: a reappraisal of the horseradish peroxidase system.
abstract: Reinvestigation by stopped-flow spectrophotometry of the previously observed influence of a static magnetic field on the horseradish peroxidase (HRP)-catalyzed reduction of hydrogen peroxide by Taraban et al. (J. Am. Chem. Soc. 1997, 119, 5768) did not reproduce the originally observed effects. No magnetic field effect was observed for static fields of up to 75 mT. Field-induced changes in both k1 and k2 reported in the original work were found to produce equal and opposite effects on the shape of the observed kinetic decay of the 418 nm spectroscopic signal as a result of the difference in the relative absorbances of Native HRP and Compound II.
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Jones
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Scrutton
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Woodward
mesh_terms: D002384:Catalysis; D004789:Enzyme Activation; D005609:Free Radicals / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D008280:Magnetics; D010084:Oxidation-Reduction
chemical_list: D005609:Free Radicals; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase