After shift to 38°C or exposure to paraquat to cause oxidant damage, recently synthesized proteins not degraded in Δrpn10 and Δubc4Δubc5 mutants selectively accumulate in the particulate fraction, unlike recently synthesized proteins in WT or mutant strains at 30°C without oxidant present. (A) WT, Δrpn10, and Δubc4Δubc5 strains were labeled with ³⁵S-Met for 5 min, washed, and shifted to 38°C or treated with paraquat at 30°C. At the indicated times, lysates were prepared, and equal amounts of lysate proteins were subjected to differential centrifugation. The amounts of labeled protein present in pellets obtained by centrifuging for 20 min at 9,300 g and by ultracentrifugation at 275,000 g for 60 min were measured. To determine the amounts of labeled long-lived proteins that accumulate in these fractions, cells were shifted to 38°C or exposed to paraquat 3 h after labeling. (B) WT, Δrpn10, and Δubc4Δubc5 strains were labeled with ³⁵S-Met for 5 min at 30°C. The amounts of radiolabeled protein present in 275,000 g pellet were measured as described in Fig. 10 A. (C) Yeast were grown exponentially and treated with paraquat as in Fig. 10 A. Cell lysates were subjected to centrifugation and the presence of carbonylated proteins in the 275,000 g pellet assayed by OxyBlot as in Fig. 3 A.