Bacitracin: Bacitracin has been shown to inhibit both the reductive and the oxidative functions of the protein PDI

Bacitracin Bacitracin has been shown to inhibit both the reductive and the oxidative functions of the protein PDI. Although the mechanism(s) of inhibition is unknown, bacitracin has been shown to inhibit the intrinsic disulfide isomerase activity of integrin αIIb β3 (O'Neill et al., 2000; Robinson et al., 2006) and fibronectin (Weston et al., 2001), proteins not related to the PDI family, but containing a CXXC motif. Thus, bacitracin can inhibit a wide range of thiol-disulfide exchange reactions. Bacitracin is transported poorly into mammalian cells and thus it inhibits PDIs at the surface of target cells (Mandel et al., 1993). Our experiments were conducted in the presence of 5% bovine fetal serum, known to inhibit any contaminant protease activity in the bacitracin preparation (Weston et al., 2001). The concentration range used in other studies for inhibiting PDI is 0.5-5 mM.