An Antiproliferative Ribonuclease from Fruiting Bodies of the Wild Mushroom Russula delica

An antiproliferative ribonuclease with a new N-terminal sequence was purified from fruiting bodies of the edible wild mushroom Rassula delica in this study. This novel ribonuclease was unadsorbed on DEAE-cellulose, but absorbed on SP-Sepharose and Q-Sepharose. It had a molecular mass of 14 kDa, as judged by fast protein liquid chromatography on Superdex 75 and SDS-polyacrylamide gel electrophoresis. Its optimal pH and optimal temperature were pH 5 and 60 degrees C, respectively. The ranking of its activity toward various polyhomoribonucleotides was poly C>poly G>poly A>poly U. It could inhibit proliferation of HepG2 and MCF-7 cancer cells with an IC50 value of 8.6 mu M and 7.2 mu M, respectively. It was devoid of antifungal and HIV-1 reverse transcriptase inhibitory activity.