Figure 6. Kinetic analysis of the dephosphorylation of pCPI-17 by PP2A-B56α, a candidate PPU enzyme.
(A). Linearity of assay employing PP2A-B56α enzyme (at 0.25 nM); the concentration of pCPI-17 was 1 μM. (B) Velocity of the dephosphorylation of pCPI-17 by 0.1 nM PP2A-B56α as a function of the concentration of the pCPI-17 substrate. Reactions were performed for 1 min at 30°C in a volume of 4 μL. The data were analyzed by Prism 6 software as in Figure 4, giving Km = 4.2 ± 0.5 μM and kcat = 29 ± 2 s−1.