CTSA Full-Length MS Protein Standard (NP_000299), 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 glycoprotein which associates with lysosomal enzymes beta-galactosidase and neuraminidase to form a complex of high molecular weight multimers. The formation of this complex provides a protective role for stability and activity. Deficiencies in this gene are linked to multiple forms of galactosialidosis. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.