Figure 7
From: A streamlined implementation of the glutamine synthetase-based protein expression system
Expression of CCL18. A. Elution profile for Ni-NTA-purified CCL18 (second peak) eluting from a Superdex 75 HR 10/30 gel-filtration column. Peak 1 corresponds to an unidentified histidine-containing impurity detectable with anti-pentahistidine antibodies on Western blots (data not shown). Fractions containing this protein lacked CCL18 reactivity according to a sandwich ELISA assay (data not shown). The elution positions of two proteins of known size (43 and 13.7 kDa) are indicated. B. SDS-PAGE analysis of the proteins eluting from the G-75 column under non-reducing conditions. The identity of the small protein in the late-eluting peak (black arrow) was confirmed as CCL18 using the ELISA assay (data not shown). The identity of the ~40 kDa protein (white arrow) was not determined.