Immunogen sequence: DPERAAARGD TFSALTSVAR ALAPERRLLG LLRRYLRGEE ARLRDLTRFY DKVLSLHEDS TTPVANPLLA FTLIKRLQSD WRNVVHSLEA S; Positive Samples: 293T; Cellular Location: Endoplasmic reticulum lumen. Catalyzes the post-translational formation of 4- hydroxyprol