By Ad on Thursday, July 1, 2004 - 04:25 pm:

Using reverse phase HPLC in-line with ESI-MS we routinely identify all the peptides resulting from CNBr cleavage of a protein...except those containing cysteine. Why? Where do these peptides go and how can I get them back? Without reductive alkylation should I expect to lose Cys-containing peptides or is there a simple solution? All comments and suggestions are very much appreciated.