Fig. 5.

Representative H₂O₂ uptake traces by LPO (5 μM) incubated with different GSH concentrations (0–2 mM) for 2 hs at 37 °C in phosphate buffer (pH 7.4, 0.1M). Two-hour incubations of LPO with GSH were stopped by rapidly freezing the samples at −80 °C. For the experiments, samples were hand-thawed and diluted into the reaction chamber. Experiments were performed in triplicate. Panel A represents the traces obtained with control LPO incubated in phosphate buffer in the absence of GSH. Panels B–D are the traces obtained when LPO was incubated with 0.15, 0.5 and 2.0 mM GSH, respectively. For those experiments, pulses of 100 μM H₂O₂ were used. NaSCN (2 mM) was added at the point marked. NaN₃ (1 mM) was added to the reaction chamber to inhibit LPO. Its point of addition is indicated as well.