Peptidase Inhibitor 3, Skin Derived (PI3)

Elafin is an elastase-specific inhibitor, which contains a WAP-type four-disulfide core (WFDC) domain, and is thus a member of the WFDC domain family. Chang et al. and Schalkwijk et al. described a low molecular weight elastase inhibitor derived from psoriatic skin and termed SKALP for 'skin-derived antileukoproteinase.' They demonstrated that this inhibitor can be found in the epidermis of several inflammatory skin diseases, but not in normal human epidermis. Wiedow et al. referred to this molecule as elafin, and Sallenave and Ryle referred to it as elastase-specific inhibitor. It is found in the urine of psoriatic patients, and immunohistochemical studies showed that SKALP/elafin is found in the suprabasal differentiated keratinocytes of psoriatic epidermis. Molhuizen et al. isolated a precursor of SKALP/elafin from cultured keratinocytes and cloned its cDNA.