Enrichment of cysteine-containing peptides from tryptic digests using a quaternary amine tag.
A new strategy for specifically targeting cysteine-containing peptides in a tryptic digest is described. The method is based on quantitatively derivatizing cysteine residues with a quaternary amine tag (QAT). Tags were introduced into proteins following reduction of disulfide bonds through derivatization of cysteine residues with (3-acrylamidopropyl)trimethylammonium chloride. After trypsin digestion, derivatized cysteine-containing peptides were enriched by strong cation exchange chromatography. The method was validated using model peptides and a protein. The QAT strategy has several advantages over other methods for the selection of cysteine-containing peptides. One is that it increases the ionization efficiency of cysteine-containing peptides. The other is that chromatographic selection is achieved with simple, robust cation exchange chromatography columns. As a result, this new strategy provides a simple way to facilitate enrichment of cysteine-containing peptides, thereby reducing sample complexity in bottom-up proteomics.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
Diya
D
Ren
Samir
S
Julka
Halina D
HD
Inerowicz
Fred E
FE
Regnier
D000595:Amino Acid Sequence; D001059:Apoproteins / Q000737:chemistry; D003545:Cysteine / Q000032:analysis*; D007202:Indicators and Reagents; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry*; D040901:Proteomics; D000644:Quaternary Ammonium Compounds; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014168:Transferrin / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry*
D001059:Apoproteins; D007202:Indicators and Reagents; D010446:Peptide Fragments; D000644:Quaternary Ammonium Compounds; D014168:Transferrin; C028284:apotransferrin; D014357:Trypsin; D003545:Cysteine