Fig. 4.
Characterization of the S756, Se, and S glycoproteins. Close to background level cleavage of S and Se. Western blots of supernatants from transfected 293 cells expressing S756, Se, and cell lysate of 293 cells expressing the S glycoproteins using the P540 antibody are shown. The left panel shows Western blots of samples kept for three days at 4 °C before analysis to monitor the effect of nonspecific protease activity on the cleavage pattern, whereas the right one—blots with samples used immediately after preparation.