ERP27 (endoplasmic reticulum protein 27 kDa) is widely expressed protein that localize to the ER and may act as proteases, protein disulfide isomerases, thiol-disulfide oxidases or phospholipases. ERP27 does not contain a CXXC active site motif indicating that it is a catalytically redox-inactive member of the protein disulfide isomerase family. Recombinant human ERP27 protein was expressed in E.coli and purified by using conventional chromatography techniques.