SCHEME 2.

Cleavage site variants of prothrombin. The sequence surrounding the two cleavage sites in prothrombin are listed for the variants used in this study. Vertical arrows denote the position of the scissile bonds in wild type prothrombin. Mutated residues are shown in red, and residues in blue denote the new N-terminal sequence following cleavage required for the expression of proteolytic activity in the product. All variants possessed the same sequence flanking the Arg²⁷¹ site as the wild type species.