Recombinant Human R-Spondin-3 produced in HEK293 cells is a polypeptide chain starting at amino acid Gln at position 22 to amino acid Val at position 201, fused to an FC, 6 x His-tag at C-terminus, containing a total of 498 amino acids and having a Mw of 47.9 kDa. The protein migrates at 61kDa on SDS-PAGE. RSPO3 is a truncated protein that lacks amino acid Gln at position 201 to amino acid H at position 272 and purified by proprietary chromatographic techniques.