CREATION OF A HIGH CYTOTOXIC ACTIVE HUMAN TUMOR-NECROSIS-FACTOR HAVING THE TRUNCATED AND MORE BASIC AMINO-TERMINUS

In order to define the structure-functional relationship of tumor necr osis factor(TNF), a mutant TNF gene was created by site-specific mutag enesis based on the PCR technique. This gene was highly expressed in E .coli cells. The amount of the recombinant protein was up to about 80% of the total cellular proteins. Through one-step ion exchange chromat ography, the mutant TNF could be purified to homogeneity. This mutein showed the molecular weight of a dimer but not a trimer. It bears the features of truncated amino terminus and increase of the basicity of a mino terminal residues. Compared with the wild type TNF, the specific activity of mutant TNF was increased by fourfold. (C) 1995 Academic Pr ess, Inc.