Peptidyl-prolyl cis-trans isomerase B (PPIB or PPIase B) is also known as Cyclophilin B (CYPB), Rotamase B, S-cyclophilin (SCYLP), is a cyclosporine-binding protein and is mainly located within the endoplasmic reticulum, which belongs to the cyclophilin-type PPIase family and PPIase B subfamily. PPIB / CYPB contains one PPIase cyclophilin-type domain. PPIases accelerate the folding of proteins and catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.