PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (By similarity). [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Binds cyclosporin A (CsA). CsA mediates some of its effects via an inhibitory action on PPIase (Probable). Strongly expressed in vegetative cells with expression levels steadily decreasing during differentiation. After 12 hours of differentiation mRNA expression levels are very. slightly expressed. Belongs to the cyclophilin-type PPIase family.