Figure 1.

Representative deconvoluted ESI‐MS spectra from the modification of the β‐domain fragment of MT1a with p‐benzoqinone (Bq). The reaction at pH 2.8 (left panel) and 6.7 (right panel) gave markedly different reaction products labelled with vertical lines for the 1, 3, 5, and 9 Bq bound masses. Note that the apo‐fragment is not indicated, its mass lies to the left of the “1” line. The fully modified fragment is indicated by the “9” line. The number of molar equivalents of Bq added in the stepwise titration is listed to the right of each panel up to 8.8.