Figure 4.

Exposure of reactive center arginine by pentasaccharide. Native PAGE at pH 8.0 of a mutant (P₁ His) antithrombin (26) in lanes 1–3, and of normal (P₁ Arg) antithrombin in lanes 4–6, is shown. In lanes 2 and 5, the antithrombins have been incubated with deiminase; in lanes 3 and 6, incubation with deiminase has been carried out in the presence of the pentasaccharide. The change in mobility consequent to deimination occurs only in lane 6, with the P₁ Arg antithrombin plus pentasaccharide.