An isolated protein, for use in treatment of wounds, is characterized in that it is secreted by the organism Lucilia sericata and it exhibits proteolytic activity against FITC-casein at a pH of 8.0 to 8.5. The protein exhibits proteolytic activity against Tosyl-Gly-Pro-Arg-AMC but not against Suc-Ala-Ala-Phe-AMC, and its proteolytic activity against FITC-casein and Tosyl-Gly-Pro-Arg-AMC is inhibited by the serine proteinase inhibitors PMSF and AMPSF. The protein is also bound by immobilized aminobenzamidine.