Figure 2.

ESI FT‐ICR mass spectra of SAP30L (residues 25–92) measured in (A) MeCN/H₂O/HOAc (49.5:49.5:1.0, v/v), (B) 20 mM NH₄OAc buffer (pH 6.8) in the presence of 1,10‐phenanthroline (100‐fold molar excess), (C) 20 mM NH₄OAc buffer (pH 6.8), and (D) 20 mM NH₄OAc buffer after oxidation for 10 min with hydrogen peroxide (10‐fold molar excess). The numbers denote different charge states. The protein concentration was 1 µM in (A) and 5 µM in other measurements. Insets show the deconvoluted isotopic distributions of SAP30L. The arrows denote peaks representing the most abundant isotopologues with their masses indicated.