Recycling of the high valence States of heme proteins by cysteine residues of THIMET-oligopeptidase

PLoS One. 2013 Nov 1;8(11):e79102. doi: 10.1371/journal.pone.0079102. eCollection 2013.

Abstract

The peptidolytic enzyme THIMET-oligopeptidase (TOP) is able to act as a reducing agent in the peroxidase cycle of myoglobin (Mb) and horseradish peroxidase (HRP). The TOP-promoted recycling of the high valence states of the peroxidases to the respective resting form was accompanied by a significant decrease in the thiol content of the peptidolytic enzyme. EPR (electron paramagnetic resonance) analysis using DBNBS spin trapping revealed that TOP also prevented the formation of tryptophanyl radical in Mb challenged by H2O2. The oxidation of TOP thiol groups by peroxidases did not promote the inactivating oligomerization observed in the oxidation promoted by the enzyme aging. These findings are discussed towards a possible occurrence of these reactions in cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocatalysis / drug effects
  • Cysteine / chemistry
  • Cysteine / metabolism*
  • Electron Spin Resonance Spectroscopy
  • Hemeproteins / chemistry
  • Hemeproteins / metabolism*
  • Horseradish Peroxidase / chemistry
  • Horseradish Peroxidase / metabolism
  • Humans
  • Hydrogen Peroxide / metabolism
  • Hydrogen Peroxide / pharmacology
  • Kinetics
  • Metalloendopeptidases / metabolism*
  • Molecular Structure
  • Myoglobin / chemistry
  • Myoglobin / metabolism
  • Oxidation-Reduction / drug effects
  • Peroxidases / chemistry
  • Peroxidases / metabolism*
  • Phosphines / pharmacology
  • Protein Multimerization / drug effects
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Spectrophotometry
  • Sulfhydryl Compounds / chemistry
  • Sulfhydryl Compounds / metabolism

Substances

  • Hemeproteins
  • Myoglobin
  • Phosphines
  • Sulfhydryl Compounds
  • tris(2-carboxyethyl)phosphine
  • Hydrogen Peroxide
  • Horseradish Peroxidase
  • Peroxidases
  • Metalloendopeptidases
  • thimet oligopeptidase
  • Cysteine

Grants and funding

We are grateful for financial support from the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, Projeto Temático Proc. 2008/04948- 0), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Universidade Federal de São Paulo (UNIFESP), Universidade Federal do ABC (UFABC) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.