Purity: > 90% by SDS - PAGE Format: Liquid. In 20mM Tris-HCl buffer (pH 8.0) containing 0.15M NaCl, 20% glycerol, 1mM DTT. FSTL1 is a protein with similarity to follistatin, an activin-binding protein. It contains an FS module, a follistatin-like sequence containing 10 conserved cysteine residues. This protein is thought to be an autoantigen associated with rheumatoid arthritis. Recombinant human FSTL1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.