Fig. 1. Identification and characterization of phosphoglycolate phosphatase (PGP) inhibitors.

a Determination of half-maximal inhibitory constants (IC₅₀) of compounds 1-3 (CP1-3, see 2D-structures on the right), using purified murine PGP and phosphoglycolate (PG) as a substrate. Error bars not shown are hidden by the symbols. The table gives IC₅₀ values (in µM) of CP1-3 for purified PGP, PDXP, or the PDXP/PGP hybrid protein composed of the PDXP catalytic core and the PGP cap domain. H.s., Homo sapiens; M.m., Mus musculus, n.d., not determined, n.s., no significant inhibition detectable. All data are mean values ± S.E.M of at least n = 3 biologically independent experiments. Inhibition of human PGP-catalyzed PG dephosphorylation by CP2 or CP3 was assessed in n = 5 or n = 4 independent experiments, respectively. Inhibition of murine PGP-catalyzed PG dephosphorylation by CP2 and CP3, and of murine PGP-catalyzed G3P dephosphorylation by CP1 was determined in n = 4 independent experiments. b Isothermal titration calorimetry measurements of the association reactions of CP1 or CP3 with murine PGP. The left panels show representative thermograms, the right panels show fitted binding curves of the isotherms. The binding data to PGP (mean values ± S.E.M from n = 3 independent experiments) are listed in the table. K_D, dissociation constant; n, stoichiometry. c In vitro activity assays with the indicated phosphatases in the presence of 40 µM CP1, CP2 or CP3. Upper panel, C2-capped HAD phosphatases; middle panel: C1-capped HAD phosphatases; lower panel: C0-capped HAD- and other phosphatases. The respective phosphatase substrates are given in the legend. Phosphatase activities in the presence of CP1-3 were normalized to the respective enzyme activities measured in the presence of the DMSO solvent control. Data are mean values ± S.E.M.; the number of n biologically independent experiments is indicated by the number of open symbols. Source data are available as Source Data File.