Mechanistic evaluation of hematin action as a horseradish peroxidase biomimetic on the 4-aminoantipyrine/phenol oxidation reaction

AGOSTINA CÓRDOBA; NOELIA ALASINO; IVANA MAGARIO; MARIANO ASTESUAIN; MARÍA LUJÁN FERREIRA

CHEMICAL ENGINEERING SCIENCE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 129 p. 249 - 259

0009-2509

Hematin, a mimetic structure of heme peroxidases,was successfully applied forH2O2-mediated condensation reaction between phenol and4-Aminoantipyrine.The catalytic action was evaluated in comparison to horseradish peroxidase (HRP) by kinetic modeling and parametrization procedure.Expected side reactions were checked and discarded as model-Relevant routes.The existence of theoxoperferryl--cation radical and oxoperferryl species of hematin,as analogues of CompoundsI and II ofHRP,can be postulated because simulated product formation fitted experimental data.However,in lightof the optimizad rate constants encountered,hematin was less active to peroxide activation and lessspecific to the coordination of phenol vs.H2O2 than HRP.The model indicated that hematin bleachingfrom key intermediate oxoperferryl was induced rather than regenerated via CompoundIII formation.Incontrast to the enzyme,the faster oxygen evolvement and the lack of precipitating polyphenol production observed with hematin after4-aminoantipyrine depletion were interpreted as accumulationof oxidising HOO radicals through the peroxide decomposition pathway.This study may be of interestfor interpreting the catalytic performance of hematin.Moreover,the replacement of the enzyme by theless-expensive and non-polyphenol-forming hematin fort his versatile colorimetric assay may provideconvenient results,especially in flow-injectioAN modes and analytical columns applications.