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12	Mass spectrum of insulin
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37	Cleavages Observed in MS/MS of Peptides
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40	PROBLEM Bank President Who robbed the bank? Biologist What protein was isolated?
41	GATHER EVIDENCE Mass Spectrometrist 1. Interview biologist who isolated the protein 2. Cleave protein to obtain peptide mixture 3. Analyze peptide mixture by MS to obtain peptide molecular masses! Police Officer 1. Interview witnesses 2. Dust for fingerprints
42	DATABASE SEARCH Police Officer Height: 5’7” Weight: 160 lbs Gender: male Age: 35-40 Fingerprints Mass Spectrometrist Approx. molecular weight: 30,000 Origin: bovine liver Peptide mass list from MS analysis: 975.4832, 1112.5368, 632.3147, 803.4134, 764.3892
43	DATABASE SEARCH RESULTS Police Officer Identifies the robber Anthony J. Felon Mass Spectrometrist Identifies the protein bovine carbonic anhydrase
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