Redox Biology (Jan 2013)

An assay for the rate of removal of extracellular hydrogen peroxide by cells

  • Brett A. Wagner,
  • Jordan R. Witmer,
  • Thomas J. van't Erve,
  • Garry R. Buettner

DOI
https://doi.org/10.1016/j.redox.2013.01.011
Journal volume & issue
Vol. 1, no. 1
pp. 210 – 217

Abstract

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Cells have a wide range of capacities to remove extracellular hydrogen peroxide. At higher concentrations of extracellular H2O2 (micromolar) the rate of removal can be approximated by a rate equation that is first-order in the concentration of H2O2 and cell density. Here we present a method to determine the observed rate constant for the removal of extracellular H2O2 on a per cell basis. In the cells examined, when exposed to 20 μM H2O2, these rate constants (kcell) range from 0.46×10−12 s−1 cell−1 L for Mia-PaCa-2 cells (human pancreatic carcinoma) to 10.4×10−12 s−1 cell−1 L for U937 cells (human histiocytic lymphoma). For the relatively small red blood cell kcell=2.9×10−12 s−1 cell−1 L. These rate constants, kcell, can be used to compare the capacity of cells to remove higher levels of extracellular H2O2, as often presented in cell culture experiments. They also provide a means to estimate the rate of removal of extracellular H2O2, rate=−kcell [H2O2] (cells L−1), and the half-life of a bolus of H2O2. This information is essential to optimize experimental design and interpret data from experiments that expose cells to extracellular H2O2.

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