4-HNE irreversibly inactivates 20S proteasome in vitro.

(A) Schematic panel of in vitro incubations. (B) Purified 20S proteasome (1 ug) was incubated for 30 min at 37°C with 4-HNE (10 or 100 µM) and proteasomal activity was measured at the end of incubation. DTT (1μ) was added to the reaction either previous or after 4-HNE incubations. Of interest, prior, but no later, incubation with DTT protected 4-hydroxi-2-nonenal inhibition of proteasomal activity. Error bars indicate SEM. Proteasomal activity [F (7, 32) = 21.37, p<0.0001]. *, p<0.05 vs. control, 4-HNE (10 µM)+DTT (before). #, p<0.05 vs. 4-HNE (10 µM).