Recombinant human consensus interferon-a (IFN-Con1) is a synthetic type of interferon-a (IFN) developed by scanning fourteen interferona subtypes and assigning the most frequently
observed amino acids in each position (Blatt et al. 1996). The specific antiviral activity of IFN-Con1 is 5- to 20-fold higher than that of other types of IFNa and has been expressed in Escherichia coli with a high protein level (Alton et al. 1983, Fieschko and Ritch 1986). To improve the stability of IFN-Con1, two IFN-Con1 mutants, cIFN (R164S) and cIFN (R22S, R164S), were constructed by comparing about thirty types of known interferon-a (Liu et al. 2002). The mutants were resistant to proteases degradation and expressed by Pichia pastoris. To obtain high cell density and high protein productivity, a fermentation technique of expressing cIFN (R164S) by Pichia pastoris was
developed in our laboratory. The production level of cIFN reached grams per liter. However, no cIFN
monomer could be isolated from the supernatant. This work has investigated the form of cIFN in the
fermentation medium: cIFN was as non-covalent aggregates and disulphide bond aggregates. In
addition, the level of non-covalent aggregated cIFN was higher than other recombinant proteins
expressed by engineered cell lines. To the best of our knowledge, the non-covalent aggregation of
interferon-a has not been reported previously |
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| Payment Terms︰ | t.t |
| Specifications︰ | specific acitivity 100Miu per mg min
RP HPLC Purity:95% min |
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