Questions tagged [mass-spec]

The tag has no usage guidance.

5 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
3 votes
0 answers
45 views

Mass spectrometry: What is meant by the 'most intense peptide ions' in data dependent acquisition (DDA) mode?

I am learning about data dependent acquisition (DDA) mode in mass spectrometry from this online resource. I have come across the following statement: In DDA mode, the mass spectrometer selects the ...
ceno980's user avatar
  • 1,671
2 votes
0 answers
40 views

Do "real" human samples tend to return fewer protein identifications in Proteomics experiments?

I'm working with bottom-up (shotgun) mass spectrometry-based proteomics and have encountered an issue. If I do a run with a HeLa digest standard, the resulting data returns many protein IDs. When I do ...
Nathan's user avatar
  • 29
2 votes
0 answers
69 views

Which mass spectrometry database search algorithms include the fragment mass accuracy in the calculation of protein scores?

E.g. in a MASCOT search, the accuracy of the fragment ions in a ms/ms spectrum does not have any influence on the scores of identified proteins (unless the fragment ions are out of the set ms/ms ...
Markus's user avatar
  • 21
1 vote
0 answers
88 views

What are protein iBAQ abundance values in SWATH mass spectrometry?

I am reading a journal paper where they used SWATH mass spectrometry to quantify the abundance of proteins in synaptosomes isolated from different species. I am trying to determine whether some ...
ceno980's user avatar
  • 1,671
1 vote
0 answers
642 views

Mass change in deamidation from Glutamine to Glutamate

To detect the deamidation from Glutamine to Glutamate in a protein, normal practise seems to be a mass spec, where it is claimed there is a change of 1 dalton. EG It is claimed that: Deamidation ...
Nick's user avatar
  • 338