Figures show the zoomed-in CID spectra at m/z 560-566 range for peak 1, 2 and 3 (RT: 53.4-54.0, 54.2-54.5 and 54.5-55.2, respectively) labelled in Figure . By comparing CID spectra of THT Cys adduct from peaks 1-3, we were only able to find THTC-Cys fragment in peaks 2 and 3. Thus, peaks 2 and 3 correspond to the Cys adducts at the first linker-payload conjugation site on THT peptide, whereas peak 1 is the cysteinylation at the second Linker-PL conjugation site.