Dansyl chloride structure

Gray, R. "Sequence Analysis with Dansyl Chloride", In "Methods In Enzymology", p. 333, Vol. XXV, "Enzyme Structure, Part B", C. H. W. Hlrs and S. N. Tlmasheff, Editors, Academic Press, New York, 1972. 

Table 4 illustrates the use of the CAR technique to develop CL kinetic-based determinations for various analytes in different fields. As can be seen, the dynamic range, limit of detection, precision, and throughput (—80-100 samples/ h) are all quite good. All determinations are based on the use of the TCPO/ hydrogen peroxide system by exception, that for p-carboline alkaloids uses TCPO and DNPO. A comparison of the analytical figures of merit for these alkaloids reveals that DNPO results in better sensitivity and lower detection limits. However, it also leads to poorer precision as a result of its extremely fast reactions with the analytes. Finally, psychotropic indole derivatives with a chemical structure derived from tryptamines have also been determined, at very low concentrations, by CAR-CLS albeit following derivatization with dansyl chloride. 

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. 

Various procedures are used to analyze protein primary structure. Several protocols are available to label and identify the amino-terminal amino acid residue (Fig. 3-25a). Sanger developed the reagent l-fluoro-2,4-dinitrobenzene (FDNB) for this purpose other reagents used to label the amino-terminal residue, dansyl chloride and dabsyl chloride, yield derivatives that are more easily detectable than the dinitrophenyl derivatives. After the amino-terminal residue is labeled with one of these reagents, the polypeptide is hydrolyzed to its constituent amino acids and the labeled amino acid is identified. Because the hydrolysis stage destroys the polypeptide, this procedure cannot be used to sequence a polypeptide beyond its amino-terminal residue. However, it can help determine the number of chemically distinct polypeptides in a protein, provided each has a different amino-terminal residue. For example, two residues—Phe and Gly—would be labeled if insulin (Fig. 3-24) were subjected to this procedure. 

Figure 5.13 shows the structures of extrinsic fluors that have been of value in studying biochemical systems. ANS, dansyl chloride, and fluorescein are used for protein studies, whereas ethidium, proflavine, and various acridines are useful for nucleic acid characterization. Ethidium bromide has the unique characteristic of enhanced fluorescence when bound to double-stranded DNA but not to single-stranded DNA. Aminomethyl coumarin (AMC) is of value as a fluorogenic leaving group in measuring peptidase activity. 

What is the purpose of derivatizing compounds Name two such compounds and tell what groups they react with. What are the structural formulas for fluorescamine and dansyl chloride ... 

Dansylation of most amino acids (Fig. 2) is optimal in the pH range 9.5-11.0 pH values higher than 11.0 are associated with increased hydrolysis, and at values below 8.0, the unreacted (protonated) form of the ammo group predominates and reaction rates are slow (Seiler, 1970). The extent of dansylation of an ammo acid depends not only on the pH of the reaction mixture, but also on the chemical structure of the amino acid. Steric hindrance around the amino group, as is present in certain branched-chain amino acids, leads to decreased stability of the dansyl derivative. In addition, rates of dansylation depend on the excess quantity of dansyl chloride used, as well as on the reaction time and temperature. Since dansyl chloride is only slightly soluble in water,... 

Derivatization with phenyl isothiocynate and methylation have been used for the structural characterization of regioisomeric glucuronides (Kassahun et ak, 1997 Prakash et ak, 2007a). Dansyl chloride has been used for the... 

The second drawback is that, at least in the early work, it was not uncommon to have only trace quantities of protein for structural analysis. Thus, isolation of the product derived from N-terminus excision was not always trivial and chromatographic separations with careful comparison of (Rate of flow) values were needed. With similar alkyl side chains, the analysis was not always straightforward. So, fluorescent indicators were sought and, in the mid-1950s, dansyl chloride ... 

Surface structures SrrS, dansyl chloride cynine, Phyco[Pg.573]

Dansyl chloride has also been used as a labeling reagent for pre-albumin. Although the structure of dansyl chloride resembles only remotely that of T4, danysl chloride also competes for the same two binding sites. By a methodology similar to that described in this chapter, 1.7 moles of the dansyl moiety were found to bind covalently when 2.1 moles of dansyl chloride per mole of prealbumin were used. In this case, virtually the entire label was found in Lys-15. 

Treatment of adenosine with sodium toluene-p-sulphinate and sodium hypochlorite gives a 50% yield of 2 -0-tosyladenosine. iV-Chloro intermediates are thought to be involved, which then give tosyl chloride by reaction with the sulphinate, but it is unclear why this procedure gives a higher yield than direct tosylation.229 Amino acids linked to (deoxy)-nucleosides via a sulphamoyl group have been reported they are structurally similar to the antibiotic ascamycin (see also Vol. 23, p.226).230 3. and 5 -0-dansyl derivatives of thymidine have been prepared, and shown to act as inhibitors of thymidine kinase from herpes simplex virus.231... 

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