Hello, Thank you very much for this wonderful program. I am trying to add a heavy 13C amino acid residue to a modified peptide but I haven't been able to do it. I've tried the settings tab --> peptides settings and I have also tried the edit --> refine --> advance --> add, but I don't see the I (C-term) bold or modified (+6). After adding the heavy 13C in settings, I go to the specific peptide do RMC --> Modify --> edit modifications, I can't see the heavy1 modification in the Isoleucine drop down list, created previously in settings.
Thanks a lot!