Production and purification of human menin from Drosophila melanogaster S2 cells using stirred tank reactor

A process was developed for producing human menin from transformed Drosophila Schneider 2 cells. Protein expression was achieved after inducing the metallothionein promoter by adding copper sulfate to cells growing in suspension in a stirred-tank reactor. Experiments in shake flasks showed that the production of menin was improved when the induction was conducted late in the exponential phase of cell growth at a concentration of 1-2×10⁷cells ml^-1, with a copper concentration of 0.2 mM for no more than 24 h. This observation was confirmed by experiments in bench-scale fermentors. Subsequently, a pilot-scale fermentation yielded 1 mg l^-1 culture of purified menin.