A method for expression of an onconase gene leading to a soluble form of th
e protein was developed. The enzymatic and cytotoxic properties of the prot
ein's recombinant forms were studied. Recombinant onconase with an addition
al N-terminal Met residue isolated in non-denaturing conditions did not sub
stantially differ from the native enzyme in ribonucleolytic activity. The a
ddition of a 33-mer peptide containing auxiliary elements for the simplific
ation of isolation and detection of the recombinant protein did not affect
the enzyme properties of onconase. The method proposed is useful for the on
conase structure-function relation studies and enables construction of onco
nase-based fusion proteins for anticancer therapy.