tRNA-lysidine synthase (, TilS, mesJ (gene), yacA (gene), isoleucine-specific transfer ribonucleate lysidine synthetase, tRNA-lysidine synthetase) is an enzyme with systematic name -lysine:tRNAâÂÂcytidine ligase (AMP-forming). This enzyme catalyses the following chemical reaction
The bacterial enzyme modifies the wobble base of the CAU anticodon of tRNA at the oxo group in position 2 of cytidine.