SERIND1 is a serine proteinase inhibitor which rapidly inhibits thrombin in the presence of dermatan sulfate or heparin. This protein contains five exons and four introns. It shares homology with antithrombin III and other members of the alpha 1-antitrypsin superfamily. Mutations in this gene are associated with heparin cofactor II deficiency. Recombinant human SERIND1 protein, fused to His-tag at N-terminus, was expressed in E.coli