Exercise MSMS7
Topic
High precursor accuracy
Requirements
User access to any Mascot server, including the Matrix Science public web site
Experimental
Proteins from human serum analysed on an FT instrument. Cysteine residues reduced and alkylated with iodoacetamide (+57). Can use precursor tolerance of 5 ppm and fragment tolerance of 0.2 Da. Trypsin with 2 missed cleavages. Quite a lot of oxidised Methionine and many cases where peak picking has taken the 13C peak instead of the 12C peak.
Data
Right-click this link: MSMS7.mgf, and choose Save target as or Save link as
Questions
- How can you distinguish between peak picking choosing the 13C peak and deamidation?
- Is there evidence of non-specific cleavage?
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