Regulation of H2O2 Transport across Cell Membranes

The presence of efficient H₂O₂ decomposing enzymes and molecules in living cells and the lack of robust assays to quantify and visualize H₂O₂ hampered many attempts to monitor its fluxes. Henzler and Steudle developed a mathematical model to describe H₂O₂ permeation through cell membranes taking the enzymatic decomposition into account. The model delivered a series of predictions, which were addressed experimentally using the algae Chara corallina. Comparing the permeability and reflection coefficients of water and H₂O₂ the authors suggested that H₂O₂ partly uses the same pathway through membranes as water does. Accordingly, the Aquaporins (AQP) inhibitor mercury chloride reduced the permeability coefficient for H₂O₂ permeation and the subsequent treatment with 2-mercaptoethanol reverted the inhibitory effects of the channel blocker. This behavior is typical of AQP-mediated processes. Then, the progress in the discovery of AQP-mediated H₂O₂ transport mechanisms resembled that of water.