Endoplasmic reticulum protein 27kDa (ERP27) is a widely expressed protein which localizes to the ER and may act as a protease, protein disulfide isomerase, thiol-disulfide oxidase or phospholipase. ERP27 doesn’t contain a CXXC active site motif indicating that it is a catalytically redox-inactive member of the protein disulfide isomerase family.