FIG. 3.

Effect of GST-Bif and SP294 on phosphorylase phosphatase activity of PP1-87B. (A) GST-Bif protein was included at the concentrations shown in a standard phosphorylase phosphatase assay with PP1-87B. Squares, GST-Bif(761-1235); triangles, GST-Bif(761-1235; F995A). (B) Phosphorylase phosphatase assays were performed with PP1-87B in the presence (squares) or absence (triangles) of 10 nM GST-Bif(761-1235) and with the concentrations of peptide 294 shown. In all assays the amount of PP1-87B was kept constant and such that (in the absence of other factors) 10% of the counts were released from phosphorylase during the assay. WT, wild type.