QTRTD1 Full-Length MS Protein Standard (NP_078914), 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 subunit of tRNA-guanine transglycosylase. tRNA-guanine transglycosylase is a heterodimeric enzyme complex that plays a critical role in tRNA modification by synthesizing the 7-deazaguanosine queuosine, which is found in tRNAs that code for asparagine, aspartic acid, histidine, and tyrosine. The encoded protein may play a role in the queuosine 5-monophosphate salvage pathway. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene.