Greater than 90% as determined by SDS-PAGE. APEX1 Human Recombinant produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 332 amino acids (1-318a.a.) and having a molecular mass of 36.9kDa. APEX1 protein is fused to a 14 amino acid T7-tag at N-terminus and is purified by standard chromatography. APEX1 Human solution (1mg/ml) containing 20mM Tris-HCl pH-8, 2mM DTT, 0.2M NaCl, and 10% glycerol.