Effective expression and purification of recombinant onconase, an antitumor protein

Several members of the RNase A superfamily are endowed with antitumor activ ity, showing selective cytotoxicity toward several tumor cell lines. One of these is onconase, the smallest member of the RNase A superfamily, which i s at present undergoing phase III clinical trials. We report here the expre ssion of recombinant onconase in Escherichia coli inclusion bodies, the cor rect processing of the protein, followed by its purification in high yields . The recombinant protein has biological and catalytic properties identical to those of the natural enzyme. (C) 1999 Federation of European Biochemica l Societies.