Figure 2. Shp2a and Shp2b proteins displayed phosphatase activity.

(a) PTP activity of pGEX, WT-Shp2a, Shp2a-D61G, WT-Shp2b and Shp2b-D61G was assayed using p-nitrophenylphosphate (pNPP) and quantified spectrophotometrically. Approximately 1 µg purified fusion protein was used in the assay. Experiments were done in quadruplicate; averages are depicted and error bars indicate standard error of the mean. (b) Equivalent amounts of fusion protein that were used in the activity assays in (a) were run on an SDS-PAGE gel and stained with Coomassie blue.