Recent Question/Assignment

From the attached MSMS spectra, determine the amino acid sequence of the peptide.
The peptide selected for fragmentation (MSMS) is a 2+ ion with a mass of 675.8Da and mass spectrometers measure mass/charge ratios. What is the peptide’s true mass?
Using the sequencing rules provided in the readings, determine the amino acid sequence of the peptide. On the spectra, label the b-series ions and the y-series ions.
Produce a table with three columns. The columns are:
Amino acid. Put the N-terminal amino acid at the top of the column and the sequence running down.
b-ion mass. Write the mass of the b-ion that corresponds to the amino acid in the sequence.
y-ion mass. Write the mass of the y-ion that corresponds to the amino acid in the sequence.
Can you identify any immonium ions that support the presence of certain amino acids in the sequence you have determined? Label these on the spectra.

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