Effect of C-terminal truncation on Ppt1p activity. (A) Phosphatase activity of full-length Ppt1p (□) or the C-terminal truncation mutant, Ppt1p (1–504) (■), was determined in the absence or presence of 250 μM AA using 32P-casein or 32P-MBP as substrate. Data are the average ± S.D. of triplicate samples from a single experiment. Similar values were obtained in three independent experiments performed under the same conditions. (B) C-terminal sequences of Ppt1p and PP5 are aligned to display the truncation sites for Ppt1p (1–504) and PP5 (1–486) . The truncation sites are indicated with the filled triangles. Bold underlined residues are conserved in both Ppt1p and PP5.