Antigen 85A, belong to the antigen 85 complex (Antigen 85A, B, C). The enzymes of the antigen 85 complex possess mycolyltransferase activity and catalyze the synthesis of the most abundant glycolipid of the mycobacterial cell wall, the cord factor. The cord factor (trehalose 6,6'-dimycolate, TDM) is essential for the integrity of the mycobacterial cell wall and pathogenesis of the bacillus. TDM is synthesized from two molecules of trehalose-6'-monomycolate (TMM) by Antigen 85A. Recombinant Mycobacterium tuberculosis Antigen 85A protein, fused to His-tag at C-terminus, was expressed in Hi-5 cell and purified by using conventional chromatography techniques.