Dear,

I am working on a project where I want to see the difference in intensities between peptides labeled with a Heavy acetyl group and not.
When I try to insert the peptide list I will give me an error and I don't know how to adjust my imput so that I can continiue

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Skyline
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The following modifications could not be interpreted.

C[+103.05421] K[+92.0655] M[+42.01057][+15.99492] M[+46.03275][+15.99492]
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OK More Info
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System.FormatException: The following modifications could not be interpreted.

C[+103.05421] K[+92.0655] M[+42.01057][+15.99492] M[+46.03275][+15.99492]
   at pwiz.Skyline.Model.ModificationMatcher.CreateMatches(SrmSettings settings, IEnumerable`1 sequences, MappedList`2 defSetStatic, MappedList`2 defSetHeavy, IProgressMonitor progressMonitor, IProgressStatus status) in C:\proj\skyline_23_1\pwiz_tools\Skyline\Model\ModificationMatcher.cs:line 65
   at pwiz.Skyline.EditUI.PasteDlg.AddPeptides(SrmDocument document, Boolean validating, IdentityPath& selectedPath) in C:\proj\skyline_23_1\pwiz_tools\Skyline\EditUI\PasteDlg.cs:line 277
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This is the error I got and it happens to the modifications that contain the Acd4 modification (4Da heavier then Ace) in combination with a sertain fixed modification (Carbamidomethylation, fixed Acd4 on K or Methionine Oxidation).

I also tried it where I gave all the modifications in the peptide modifications tab and specify what modifications are in the sample and which ones should be fixed or variable.

In the latter case, I just had double the ammount of peptides where one would be with an Acd4 label and the other without.

I can send you a dat and raw file for 1 of the samples (in total 32) to have a look if you can find a way around this problem.
I will also send you the list of peptide sequences and also the one where I added the Modifications.

F010708.dat contains the NH2 searches
F010740.dat contains the Acd4 searches


Thanks in advance for the help
Lode Denolf