Figure 8.

Enzymatic analysis of His₆-AtSLP1 and His₆-AtSLP2. A, Metal dependency assessment of each SLP phosphatase was performed using a variety of metal cations as well as 5 mm EDTA. B, Analysis of known Ser/Thr phosphatase inhibitors employed at concentrations known to fully inhibit bacterially expressed and purified human and Arabidopsis PP1 protein phosphatases. Dark gray bars represent His₆-AtSLP1, while light gray bars represent His₆-AtSLP2. Assays were conducted as outlined in “Materials and Methods” and were performed with or without OA, MC-LR, At-I2 (At5g52200), PPi, Pi, and NaF. One hundred percent enzyme activity in A and B is defined by the presence of 0.5 mm Mn²⁺ (AtSLP1 assays) or 5 mm EDTA (AtSLP2 assays). Each bar represents n = 3, and error bars indicate se.