ERP29 Full-Length MS Protein Standard (NP_006808), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene encodes a reticuloplasmin, a protein which resides in the lumen of the endoplasmic reticulum (ER). The protein shows sequence similarity to the protein disulfide isomerase family. However, it lacks the thioredoxin motif characteristic of this family, suggesting that this protein does not function as a disulfide isomerase. The protein dimerizes and is thought to play a role in the processing of secretory proteins within the ER. Alternative splicing results in multiple transcript variants encoding different isoforms.