MBB 222 Chapter Notes - Chapter 5.2: Edman Degradation, Electrospray Ionization, Mass Spectrometry

• School: Simon Fraser University
• Department: Molec Biol & Biochem
• Course: MBB 222
• Professor: Michel Leroux

Document Summary

Chapter 5. 2: working with oligopeptides sequencing and synthesis. In this procedure, the pitc-modified peptide is treated with trifluoroacetic acid. This cleaves the poly- peptide bond between the first and second amino acid, releasing a thiazolinone derivative and the original polypeptide less one amino acid. The thiazolinone derivative is isolated by an organic extraction and converted to a phenylthiohydantoin (pth) derivative, which is identified by chromatography against known pth-amino acid standards. The next amino acid in the polypeptide chain is identified by repeating the n-terminal tagging reaction using the same protein sample followed by cleavage with trifluoroacetic acid and identification by chro(cid:373)atography. The ad(cid:448)a(cid:374)tage of the ed(cid:373)a(cid:374) degradatio(cid:374) procedure o(cid:448)er sa(cid:374)ger"s original protein sequencing method is that it does not require the input of additional protein after each round of cleavage. Mass spectroscopy measures the mass to charge ratio (m/z) of molecules, which is then used to deduce the molecular mass.