ISOLATION AND CHARACTERIZATION OF A TYPE-1 RIBOSOME-INACTIVATING PROTEIN FROM FRUITING BODIES OF THE EDIBLE MUSHROOM (VOLVARIELLA-VOLVACEA)

A novel single-chained ribosome-inactivating protein (RIP) with a mole cular weight of similar to 29000 was purified from fruiting bodies of the edible mushroom Volvariella volvacea with a procedure involving am monium sulfate precipitation, ion-exchange chromatography on DEAE-cell ulose, and gel filtration on Superdex 75. The mushroom RIP, designated volvarin, exhibited a potent inhibitory action on protein synthesis i n the rabbit reticulocyte lysate system with an IC50 value of 0.5 nM. Like most plant RIPs, volvarin acted as an N-glycosidase that depurina ted rRNA from rabbit reticulocyte lysate, releasing a characteristic R NA fragment after treatment with aniline. It also exerted a deoxyribon uclease activity on supercoiled SV-40 DNA and demonstrated a strong ab ortifacient effect in mice.