FIGURE 4.

Identification of mutated variants of NRAS and WT NRAS by mass spectrometry. (A) Assigned MS/MS spectrum of the TMT‐labeled peptide QVVIDGETCLLDILDTAGK corresponding to the mutation NRAS Q61K. (B) Assigned MS/MS spectrum of the TMT‐labeled peptide QVVIDGETCLLDILDTAGR corresponding to the mutation NRAS Q61R. (C) Assigned MS/MS spectrum of the TMT‐labeled peptide QVVIDGETCLLDILDTAGQEEYSAMR of WT NRAS. The Q61K/R mutations introduced an additional trypsin cleavage in the sequence of the WT protein, rendering shorter mutated peptides lacking the C‐terminal part (‐EEYSAMR) of the WT peptide sequence