Serpins and their roles in blood coagulation of early vertebrates.

<p>Angiotensinogen, HCII and an SpnV4_1-like serpin are proposed as principal regulators of the primordial procoagulant system (A). The ancestral clotting cascade presumed to be present in the last common ancestor of jawless fish and gnathostomes is based on the scheme suggested by Doolittle <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097879#pone.0097879-Doolittle2" target="_blank">[11]</a>. The coagulation scheme of mammals and its serpin inhibitors are shown for comparison (B).