Cyclophilin-33, or Peptidylprolyl isomerase E (cyclophilin E), is a human gene encoded by PPIE. It may also be known as: Peptidyl-prolyl cis-trans isomerase E; Cyclophilin E; Cyclophilin-33; Rotamase E; PPIase E; cyclophilin 33; peptidylprolyl isomerase E, isoform 1; CYP-33; CYP33. The encoded protein is an enzyme with an amino acid length of 301 and a mass of 33.4 kDa. Other isoforms may exist. Cyclophilin-33 is a member of the Cyclophilin-type PPIase family, PPIase E subfamily. Homologs of this gene exist in other organisms, including: Rat.