The function of QTMAN (queuosine-tRNA mannosyltransferase, ENSG00000121964) is as follows. Glycosyltransferase that specifically catalyzes mannosylation of cytoplasmic tRNA(Asp) modified with queuosine at position 34 (queuosine(34)) (PubMed:37992713). Mannosylates the cyclopentene moiety of queuosine(34) in tRNA(Asp) to form mannosyl-queuosine(34) (PubMed:37992713). Mannosylation of queuosine(34) in tRNA(Asp) is required to slow-down elongation at cognate codons, GAC and GAU, thereby regulating protein translation (PubMed:37992713). .