TARS (Threonyl-tRNA synthetase, cytoplasmic) belongs to the class-II aminoacyl-tRNA synthetase family. This protein has its main role in tRNA aminoacylation. The N-terminal domain of the enzyme is responsible for the competition with the ribosome whilst the catalytic and the C-terminal domain are involved in binding the two anticodon arm-like structures in the operator. Recombinant human TARS protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.