Abstract: Disclosed are a method of producing a target protein in a biologically-active, soluble form in prokaryotic cells and polycistronic vectors therefor.

Abstract: The present invention provides a genetically engineered fusion protein consisting of hEGF that is internalized inside of the cells after tracing down the cancer cells expressing hEGF receptors and human angiogenin that is cytotoxic by degrading ribonucleotide upon internalization, a process for preparing a fusion protein in a large quantity by transforming E. coli with the expression vectors containing the gene encoding the fusion protein, and pharmaceutical application of the fusion protein as an anticancer agent. All components of the fusion protein form no antibodies and exhibit no immunotoxicity since they are derived from human. Each component alone is inactive to the cancer cells, however, once they are fused together, they kill the cancer cells selectively with a difference of 1000 fold in IC50 in spite of its low molecular weight. Therefore, the fusion protein of the present invention is capable of treating the cancer expressing hEGF receptors at high level without showing toxicity.