FIGURE 2.

Effects of glutathione exposure on the activity of pre-oxidized 20 S or 26 S proteasomes. 20 S CP or 26 S proteasomes were incubated with H₂O₂ (100 μm) for 15 min and then the rate of (A) chymotrypsin-like or (B) trypsin-like activity was measured after exposure to increasing concentrations of GSH (0–1 mm). Representative traces show the rates of AMC fluorescence obtained after incubation of purified 20 S CP or 26 S proteasomes with the fluorogenic substrates AMC-Suc-Leu-Leu-Val-Tyr-AMC or Boc-Leu-Arg-Arg-AMC.