Tetsuo Oka

Production of active human interferon-β inE.coli I. Preferential production by lower culture temperature

SummaryUnusually low culture temperature, such as 20°C, was shown to be preferable for the synthesis of active human interferon-β (IFN-β) inE.coli harboring a recombinant plasmid. TheE.coli cells cultured at 20°C gave 8.6-fold higher IFN-β activity than those cultured at 37°C. However, almost the equal amounts of IFN-β protein were accumulated in both cells cultured at 20°C and at temperature higher than 20°C, suggesting that IFN-β might exist as an active form in the cells cultured at 20°C, while as a rather denatured form in the cells cultured at higher temperature.

Production of active human interferon-β inE.coli II. Optimal condition for induced synthesis by 3,β-indoleacrylic acid

SummaryThe maximum level of human interferon-β activity was expressed under the control of theE.coli tryptophan promoter whenE.coli cells were induced at late logarithmic growth phase by 3,β-indoleacrylic acid (IAA). The level is one order of magnitude higher than that obtained when the cells were induced at early logarithmic or stationary phase. When IAA was subsequently further added, the decrease in the activity observed at a latter period of fermentation was suppressed.