tRNA aspartic acid methyltransferase 1（TRDMT1) is a member of the C5-methyltransferase family. TRDMT1 specifically methylates cytosine 38 in the anticodon loop of tRNA（Asp). TRDMT1 is a protein responsible for the methylation of aspartic acid transfer RNA， particularly at the cytosine-38 residue in the anticodon loop. In addition， the TRDMT1 enzyme has residual DNA-（cytosine-C5) methyltransferase activity. TRDMT1 is expressed ubiquitously； however it has a higher expression in the testis， ovary and thymus and at much lower levels in the spleen， prostate， colon， small intestine， and peripheral blood leukocytes. Though similar in sequence and structure to DNA cytosine methyltransferases， the TRDMT1 gene is distinctive and extremely conserved in its function between taxa.
