Dansyl chloride peptide analysis

Most HPLC instruments monitor sample elution via ultraviolet (UV) light absorption, so the technique is most useful for molecules that absorb UV. Pure amino acids generally do not absorb UV therefore, they normally must be chemically derivatized (structurally altered) before HPLC analysis is possible. The need to derivatize increases the complexity of the methods. Examples of derivatizing agents include o-phthaldehyde, dansyl chloride, and phenylisothiocyanate. Peptides, proteins, amino acids cleaved from polypeptide chains, nucleotides, and nucleic acid fragments all absorb UV, so derivatization is not required for these molecules. 

The amino-terminal (N-terminal) residue of a protein can be identified by reacting the protein with a compound that forms a stable covalent link with the free a-amino group, prior to hydrolysis with 6 M HC1. The labeled N-terminal amino acid can then be identified by comparison of its chromatographic properties with standard amino acid derivatives. Commonly used reagents for N-terminal analysis are fluorodinitrobenzene and dansyl chloride. If this technique was applied to the oligopeptide above, the N-terminal residue would be identified as Val, but the remainder of the sequence would still be unknown. Further reaction with dansyl chloride would not reveal the next residue in the sequence since the peptide is totally degraded in the acid hydrolysis step. 

Peptide analysis, sequencing and synthesis All fluorescent dye labels with reactive groups for amine, dansyl chloride, dabsyl chloride. Fluorescent isothiocyanates. N-Terminal amino acid analysis, peptide sequencing, peptide synthesis, labeling peptides in solution, solid-phase synthesis of labeled peptides 37... 

Greenstein, J. P. and Winitz, M., Sequential Analysis of Peptides in Chemistry of the Amino Acids, p. 1512. New York, J. Wiley and Sons 1961 Gray, W. R., Dansyl Chloride Proc ure in Methods of Enzymology, Vol. 11 (Hirs, C. H. E., ed) pp. 139-151, New York, Acad. Press 1967 Ambler, R. A. Enzymic Hydrolysis with Carboxypeptidase, ibid. pp. 155-156... 

Edman has also devised the highly sensitive "dansyl" method in which a peptide is treated with 5-dimethyl-aminonaphthalenesulfonyl chloride, followed by acidic hydrolysis. A derivative of the N-terminal residue is obtained which can be followed during its analysis by virtue of its characteristic fluorescence. What is the derivative Why does it survive the acid treatment that cleaves the peptide bonds ... 

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