F8A2 Full-Length MS Protein Standard (NP_001007524), 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 is part of a region that is repeated three times on chromosome X, once in intron 22 of the F8 gene and twice closer to the Xq telomere. This record represents the middle copy. Although its function is unknown, the observation that this gene is conserved in the mouse implies it has some function. Unlike factor VIII, this gene is transcribed abundantly in a wide variety of cell types.