TST Full-Length MS Protein Standard (NP_003303), 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 is one of two neighboring genes encoding similar proteins that each contain two rhodanese domains. The encoded protein is localized to the mitochondria and catalyzes the conversion of thiosulfate and cyanide to thiocyanate and sulfite. In addition, the protein interacts with 5S ribosomal RNA and facilitates its import into the mitochondria. Alternative splicing results in multiple transcript variants.