FIGURE 3.

Analytical heparin-Sepharose column elution profiles for thrombin, α₁AT^pitts, and their complex. A, elution profile of proteins and complexes, as indicated. It can be seen that α₁AT^pitts, native or cleaved (peaks 1 and 4), does not bind to heparin-Sepharose and elutes in the void volume. Thrombin and thrombin bound to PPACK bind to the heparin column with high affinity and elute late in the NaCl gradient (gray line). Thrombin-α₁AT^pitts complex, whether intact (peak 3) or nicked by excess thrombin (peak 5), has weaker affinity for heparin-Sepharose than native thrombin. mAU, milliabsorbance units. B, non-reducing SDS-PAGE analysis of the peaks labeled in A. MW, molecular weight.