Figure 2.
TMT reactivity of lysis buffer components and TMTpro titration. (A) Structure of TMTpro. (B) Hypothetical product of TMTpro-DTT, showing that TMT reacts with the thiol group in DTT. (C) Titration of the TMTpro zero reagent. Human brain tissue lysate (5 μg tissue containing ~0.5 μg protein) was digested and directly labeled by TMTpro zero with various TMT/tissue ratios (w/w in triplicates) for 30 min. The labeled peptides were analyzed by LC-MS/MS. The percentage of labeled peptides was defined by quantifying unlabeled peptides in each run, compared to the control run (i.e. unlabeled sample). The titration experiment was replicated (n = 3) with the standard deviation of the mean shown.