Recombinant human TPBG (trophoblast glycoprotein), also known as Wnt-activated inhibitory factor 1 (WAIF1), encompassing amino acids 32-355. This construct contains a C-terminal Avi-tag™ followed by a His-tag (6xHis). The recombinant protein was enzymatically biotinylated using Avi-Tag technology and affinity purified.