Antileukoprotease in psoriatic scales

Abstract

Antileukoprotease is known to be an antiproteolytic compound of mucous secretions in humans. While searching for peptide-like inhibitors of neutrophil-derived serine proteases in horny layers of human skin, we isolated a potent inhibitor of human leukocyte elastase (EC 3.4.21.37) and cathepsin G (EC 3.4.21.20) from psoriatic scales. This inhibitor showed inhibitory constants for human leukocyte elastase of approximately 0.5-2 × 10-10 M and for cathepsin G of 2-4 × 10-9 N. The N-terminal amino acid sequence of the purified peptide matched the sequence of antileukoprotease and both peptides showed the same Mr on SDS-PAGE. Therefore, antileukoprotease may not only regulate serine protease activities in mucous secretions, but also in skin. © 1993.