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Use of Cysteine Aminoethylation To Identify the Hypervariable Peptides of an Antibody
- DeGraan-Weber, Nick, Reilly, James Patrick
- Analytical chemistry 2018 v.90 no.3 pp. 1608-1612
- antibodies, cysteine, peptides, trypsin
- Aminoethylation of cysteines can provide enzymatically cleavable sites. The ability to obtain peptides containing antibody complementarity determining regions (CDRs) with aminoethylated cysteines was investigated. Because cysteines are often located N-terminal to CDRs, digestion with Lys-N enables acquisition of peptides with CDRs. Lys-N peptides containing an aminoethylated cysteine at the N-terminus were also amidinated. Subsequent collisional activation yields a unique loss of 118 Da that originates from this modified residue, providing a signature ion for cysteine-containing peptides. The relative cleavage efficiencies for Lys-N and trypsin are also compared.