Production of functional rat liver PSP protein in Escherichia coli

An efficient Escherichia coli expression system for the production of a per chloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGE X4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-beta-D-galaetopyranoside (IPTG), the recombinant product was purifi ed by glutathione-Sepharose 4B affinity chromatography. The purified produc t showed the expected NH2-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authenti c PSP isolated from rat liver.