Figure 4. Confirmation of the presence of phosphatase activity.
(A) Increase in the detection of the phosphatase reaction product, PNP, over a range of exogenously added PTP1B. Insert: Absorption maxima for PNPP and PNP. (B) Effect of exogenously added PTP1B on the cleavage of PNPP and production of PNP in the same experimental conditions as those used in Figure 2. Also indicated is the effect of DTT, ZnCl2 and EDTA on phosphatase activity in. Data represent mean ± SEM of 3 independent experiments in duplicate.