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Figure S2. Rapid degradation of pDPAPB in sbh1Δsbh2Δ cells. A culture of sbh1Δsbh2Δ cells was prepared for pulse-chase labeling at 30°C with Tran-³⁵S-label as described in Materials and methods. Aliquots of cells (4 A₆₀₀) were removed after the 7-min pulse and at 10-min intervals during the chase. Nontranslocated pDPAPB, translocated DPAPB, and mature DPAPB (mDPAPB) were recovered by immunoprecipitation using anti-DPAPB antibodies and resolved by PAGE in SDS. Radiolabeled polypeptides were quantified with a molecular imager and are expressed relative to the quantity of unglycosylated pDPAPB (circles) and DPAPB plus mDPAPB (squares) detected after the 7-min pulse. The rapid disappearance of pDPAPB (t_1/2 = 7 min) is not accompanied by a net increase in the amount of DPAPB plus mDPAPB. Plotted values represent a single determination.