Figure 4

SDS-PAGE of eluted solutions from Ni-NTA columns of cell extracts derived from bioreactor cultures of E. coli strain BL21 (mHO1) harvested at various times during growth on ZY medium. Gel lanes are: mixture of protein molecular size standards (a), and cell extracts from cultures harvested at 2h, (b), 5h (c), 10h (d), 15h (e) and 25 h (f) after culture inoculation. Expression of 29Kd ho1 is evident (right arrow) and not visible when derived from cells grown without lactose or glucose + IPTG (not shown). Gel positions of 37Kd and 25Kd protein markers are indicated by arrows (left side).