Figure 3.

Protein phosphatase type 2C activity of a GST-LjNPP2C1 protein. (A) Experiments showing a time-dependent dephosphorylation of ³²P-labeled casein by a recombinant GST-LjNPP2C1 protein in the presence of 20 mM magnesium acetate and 1 μM okadaic acid. The GST protein alone was ineffective in this assay (data not shown). (B) Divalent cation requirement for the protein phosphatase activity of LjNPP2C1. The recombinant GST-LjNPP2C1 protein was assayed for its PP2C activity in the presence of Mg²⁺, Mn²⁺, or Ca²⁺ or in the absence of a divalent cation and in the presence of EDTA. “GST” denotes the assay performed in the presence of the GST protein alone.