This is a family of IPP transferases EC:2.5.1.8 also known as tRNA delta(2)-isopentenylpyrophosphate transferase. These enzymes modify both cytoplasmic and mitochondrial tRNAs at A(37) to give isopentenyl A(37) [2].

1: The modified nucleoside 2-methylthio-N6-isopentenyladenosine in tRNA of Shigella flexneri is required for expression of virulence genes. Durand JM, Bjork GR, Kuwae A, Yoshikawa M, Sasakawa C; J Bacteriol 1997;179:5777-5782. PMID:9294434

2: Subcellular locations of MOD5 proteins: mapping of sequences sufficient for targeting to mitochondria and demonstration that mitochondrial and nuclear isoforms commingle in the cytosol. Boguta M, Hunter LA, Shen WC, Gillman EC, Martin NC, Hopper AK; Mol Cell Biol 1994;14:2298-2306. PMID:8139535

3: MOD5 translation initiation sites determine N6-isopentenyladenosine modification of mitochondrial and cytoplasmic tRNA. Gillman EC, Slusher LB, Martin NC, Hopper AK; Mol Cell Biol 1991;11:2382-2390. PMID:1850093