Figure 3: Determination of free thiols by IAA alkylation of GRNs.
Holoproteins from Fig 2 were used for alkylation reactions using 1 mM iodoacetamide (IAA) and aliquots of samples were analyzed using MALDI-ToF-MS. The spectra of alkylated samples of Cu incubated GRN-3 (a) and GRN-5 (b) in a pH 7.0 buffer and GRN-3 (c) and GRN-5 (d) in pH 4.5. e-f) MALDI-ToF-MS spectra of apoGRNs at the two pH conditions tested. i) The spectra of alkylation reactions of GRN-3 and −5 incubated with other metal-ions (Ca, Co, Mg, Mn, Ni and Zn) at neutral and acidic pH.