PURIFICATION AND CHARACTERIZATION OF CYSTEINE PROTEASE FROM PLEUROTUS-OSTREATUS

Cysteine protease activity in mycelial culture increased 7.7-fold afte r 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-chlorom ercuribenzoate, N-ethylmaleimide, and HgCl2. The sequence of the first 9 N-terminal amino acids of cysteine protease was ASGLXXAIL.