FIGURE 5.

Exosite ligands protect thrombin-serpin complexes from autolysis. A, cleavage at exosite II (bands a and g) of thrombin in complex with AT is decreased with increasing concentration of 10-mer heparin (10mer hep, from 0.4 to 1 mm, indicated by ramp). MW, molecular weight. B, heparin and hirugen confer protection from proteolysis, but TM456 does not. C, all tested thrombin-serpin complexes (α₁AT^pitts, AT, and PN1) result in similar cleavage patterns on SDS-PAGE and are similarly protected from limited proteolysis by hirugen.