Fig. 2. Silver ions bind to cysteines of GAPDH. (A) MALDI-TOF mass spectrum of apo-GAPDH and GAPDH after incubation with 3 and 8 eq. of Ag⁺. (B) Ag⁺-binding capability of WT GAPDH and its variants measured by ICP-MS (n = 3). (C) Free thiol contents in GAPDH measured by Ellman's assay (n = 3). (D) Isothermal titration calorimetry (ITC) results of Ag⁺ binding to WT GAPDH and GAPDH^3CS (n = 3). The data were fitted to a one-set-of-site binding model using Origin software. One representative of three replicates is shown (C). The results are shown as mean ± SEM (B).