(A) Phosphatase assays were performed with PPH-5 and five identified compounds. The substances (50 ng/ml) P5SA-1 (yellow), P5SA-2, (orange), P5SA-3, (red), P5SA-4 (blue) and P5SA-5 (green) activate PPH-5 (DMSO control in black). (B) Chemical structures of the five activators. (C) Phosphatase assays of human PP1 (yellow), PP2A (orange) and PP2B/PP3 (red), as well as the BIAP (blue). For comparison, PPH-5 is depicted in black. Compound concentrations were the maximal stable concentrations outlined in the materials and methods section. Results are expressed as mean ± S.D. (n≥3).