SPINT2 is a transmembrane protein with two extracellular Kunitz domains that inhibits a variety of serine proteases. The protein inhibits HGF activator which prevents the formation of active hepatocyte growth factor. This protein is a putative tumor suppressor, and mutations in this protein result in congenital sodium diarrhea. Recombinant human SPINT2 protein, fused to His-tag at N-terminus, was expressed in E.coli.