Fig. 1: Structures of ligands used in this study and their rates of hydrolysis by AtPFA-DSP1.

Michaelis–Menten kinetic plots are shown for the phosphatase activities of AtPFA-DSP1 towards: (a), 5-InsP₇, (b), 1,5-InsP₈, (c), 6-InsP₇, (d), 5-PP-InsP₄ and (e), 4-InsP₇. Activity data (circles, some overlapping) are from each independent experiment at which the indicated substrate concentration was tested; the total number of such experiments is given above each data set in blue font. K_m values were calculated when statistically appropriate. The insets in panels (a–e) depict chair conformations of each substrate; the positions of each β-phosphate are emphasized in red. In panel (f), vertical bars represent mean values of activities against the weakest substrates when all were assayed at 10 µM concentrations. Activity data (circles, some overlapping) are from each independent experiment; the total number of such experiments is given above each data set in blue font. Phenylphosphate is abbreviated as Phenyl-P. Structures of the inositol phosphates are given as chair conformations in panels (g) (1-InsP₇), (h) (2-InsP₇, (i) (3-InsP₇) and (j) (InsP₆). Locants (using standard nomenclature for myo-inositol) are provided with the structures of 5-InsP₇ and InsP₆. Source data are provided as a Source Data file.