Purification and Characterization of Cysteine Protease from Pleurotus ostreatus

Abstract

  Cysteine protease activity in mycelial culture increased 7.7-fold after fruit body formation in Pleurotus ostreatus, using the Leu pNA (LPNA) cleavage assay. The enzyme was purified from fruit bodies and its M_r was 97,000 by gel filtration and 48,500 by SDS-PAGE, indicating that it is a dimer. The enzyme was sensitive to iodoacetic acid, p-chloromercuribenzoate, N-ethylmaleimide, and HgCl₂. The sequence of the first 9 N-terminal amino acids of cysteine protease was ASGLXXAIL.