A seventeen kilodaltons peptidyl-prolyl cis-trans isomerase of the cyclosporin-producer Tolypocladium inflatum is sensitive to cyclosporin A.

A peptidyl-prolyl cis-trans isomerase (PPIase) was purified to homogeneity about 24-fold from the cyclosporin-producing fungus Tolypocladium inflatum. The molecular mass of the enzyme was in the range of 17 kdaltons. Remarkably, the enzyme could be inhibited by cyclosporin A in the nanomolar range as has been shown for numerous other cyclophilins from eukaryotic organisms. This indicates, that Tolypocladium inflatum must possess a self protection system in order to survive in the presence of cyclosporin.