... thusblocking protein synthesis and leading cells to death. The current model proposed for the mechanism of antitumouraction of BS-RNase is based on the ability of the proteinto resist the neutralizing ... (data not shown).It is noteworthy that in the inactive MCM, MCA andMAE monomers Cys31 and Cys32, the cysteine residuesoriginally involved in the intersubunit disulfide bondingof BS-RNase, are ... cannot fit into the horseshoe cavity of the inhibitor, whereas a monomeric form of the enzymecan, and is fully inhibited by CRI. Indeed, monomericRNases lacking cytotoxic activity, such as bovine...