Purification and characterization of a novel acid phosphatase from the split gill mushroom Schizophyllum commune

A monomeric acid phosphatase (ACP) with a molecular mass of 72.5kDa was purified from fresh fruiting bodies of cultured Schizophyllum commune mushroom. The isolation procedure entailed ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. It demonstrated a unique N-terminal amino acid sequence of NAPWAQIDEV, which exhibited 60% amino acid identity to that of S. commune hypothetical histidine ACP based on its genome sequence, but less than 30% amino acid identity to that of other fungal ACPs previously reported. The ACP exhibited an optimum temperature at 50 degrees C, an optimum pH at pH 4.6, and was considerably stable at a pH range of 4.0 to 9.0, and a temperature range of 20-40 degrees C. The K-m of the purified enzyme for -nitrophenyl phosphate (NPP) was 0.248mM and the V-max was 9.093x10(-3)M/min. ACP activity was strongly inhibited by Al3+ and Fe3+, but enhanced by Co2+, Mg2+, and Ca2+ at a concentration of 0.5 mM.