Novel cathepsin L-like protease from dermestid beetle Dermestes frischii maggot

A novel cathepsin L-like protease from dermestid beetle Dermestes frischii maggot guts was obtained and investigated. The protease was isolated through affinity chromatography at arginine-diasorb followed by FPLC gel-filtration at Superdex 75. Protease is active against chromogenic peptide substrates, containing Arg or Leu in P1 position and a hydrophobic residue in P2 position. PH optimum is about 4,5 and temperature optimum at 40 °C. Enzyme is inhibited completely by HgCl2 and leupeptin that prove it’s belonging to cysteine proteases of papain family.cDNA analysis of cathepsin L-like protease showed that protein sequence consists of 339 amino acid residues. Mature cysteine protease contains 219 amino acid residues corresponding to molecular mass 24027.20 Da. Residues of the active site were identified: Gln140, Cys146, His285, Asn306 and Trp308. Calculated pI is 4,73. The amino acid sequence of the cystein protease from dermestid beetle displays high structural homology with cathepsin L of other insects.