ppiA also kmown as Peptidyl-prolyl cis-trans isomerase A. This protein is PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Recombinant E.coli ppiA protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.