Immunophilin

In molecular biology, an immunophilin is a protein that binds to immunosuppressive drugs such as rapamycin, cyclosporin, and FK-506. For these drugs in particular, known immunophilins such as cyclophilin catalyze the cis-trans isomerization of peptide bonds, particularly X-Pro peptide bonds. However, this isomerase activity appears to be unrelated to their ability to bind these drugs.