Ppif also known as Peptidyl-prolyl cis-trans isomerase F, mitochondrial. Ppif accelerates the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and involved in regulation of the mitochondrial permeability transition pore (mPTP). It is proposed that its association with the mPTP is masking a binding site for inhibiting inorganic phosphate (Pi) and promotes the open probability of the mPTP leading to apoptosis or necrosis the requirement of the PPIase activity for this function is debated. Recombinant rat Ppif was expressed in E.coli and purified by using conventional chromatography techniques.