A pulse radiolysis investigation of the reactions of myeloperoxidase with superoxide and hydrogen peroxide

Anthony J. Kettle*, David F. Sangster, Janusz M. Gebicki, Christine C. Winterbourn

*Corresponding author for this work

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Using pulse radiolysis, the rate constant for the reaction of ferric myeloperoxidase with O2- to give compound III was measured at pH 7.8, and values of 2.1 · 106 M-1 · s-1 for equine ferric myeloperoxidase and 1.1 · 106 M-1 · s-1 for human ferric myeloperoxidase were obtained. Under the same conditions, the rate constant for the reaction of human ferric myeloperoxidase with H2O2 to give compound I was 3.1 · 107 M-1 · s-1. Our results indicate that although the reaction of ferric myeloperoxidase with O2- is an order of magnitude slower than with H2O2, the former reaction is sufficiently rapid to influence myeloperoxidase-dependent production of hypochlorous acid by stimulated neutrophils.

Original languageEnglish
Pages (from-to)58-62
Number of pages5
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number1
Publication statusPublished - 31 Aug 1988



  • Hydrogen peroxide
  • Myeloperoxidase
  • Pulse radiolysis
  • Superoxide

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