[Recombinant human lymphotoxin: synthesis in Escherichia coli cells, purification, and certain properties]

The biosynthesis of recombinant human lymphotoxin produced by E. coli SG20050/pLT21 cells and deprived of 21 amino acid residues has been studied. It has been shown that the bulk of the recombinant protein in E. coli cells is in the soluble form and predominantly localized in the cytoplasm. The maximal synthesis of soluble recombinant lymphotoxin is achieved during 24-hour cultivation of producing strain cells at 32 degrees C. A procedure for isolation and purification of the recombinant protein from E. coli cells has been developed. The purification is accomplished by gel-filtration on Sephadex G-150, ion-exchange chromatography on DEAE-Sephadex and CM-Sephadex, resulting in 97-fold purification and a 62% yield. The specific activity of the protein is about 1-10(8) U per mg of protein. Some physico-chemical properties of the recombinant protein have been studied.