dansyl chloride

{{chembox

| Watchedfields = changed

| verifiedrevid = 443561047

| Reference = {{cite web |url=http://www.sigmaaldrich.com/catalog/search/ProductDetail/FLUKA/39220 |title=MSDS |publisher=Sigma-Aldrich |access-date=2007-12-02 |url-status=dead |archive-url=https://web.archive.org/web/20071227092756/http://www.sigmaaldrich.com/catalog/search/ProductDetail/FLUKA/39220 |archive-date=2007-12-27 }}

| ImageFile = Cloruro di 5-dimetilamminonaftalen-1-solfonile struttura.svg

| ImageSize = 160

| ImageAlt = Skeletal formula

| ImageFile1 = Dansyl-chloride-3D-balls.png

| ImageSize1 = 160

| ImageAlt1 = Ball-and-stick model

| PIN = 5-(Dimethylamino)naphthalene-1-sulfonyl chloride

| OtherNames =

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 11308

| InChI = 1/C12H12ClNO2S/c1-14(2)11-7-3-6-10-9(11)5-4-8-12(10)17(13,15)16/h3-8H,1-2H3

| InChIKey = XPDXVDYUQZHFPV-UHFFFAOYAI

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C12H12ClNO2S/c1-14(2)11-7-3-6-10-9(11)5-4-8-12(10)17(13,15)16/h3-8H,1-2H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = XPDXVDYUQZHFPV-UHFFFAOYSA-N

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 605-65-2

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = QMU9166TJ4

| PubChem = 11801

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 51907

| SMILES = ClS(=O)(=O)c1cccc2c1cccc2N(C)C

| RTECS = QK3688000

}}

|Section2={{Chembox Properties

| C=12 | H=12 | Cl=1 | N=1 | O=2 | S=1

| Appearance =

| Density =

| MeltingPtC = 70

| BoilingPt =

| Solubility =

}}

|Section3={{Chembox Hazards

| GHSPictograms = {{GHS05}}

| GHSSignalWord =

| HPhrases = {{H-phrases|314}}

| PPhrases = {{P-phrases|260|264|280|303+361+353|304+340|305+351+338|310|321|363|405|501}}

| FlashPt =

| AutoignitionPt =

}}

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Dansyl chloride or 5-(dimethylamino)naphthalene-1-sulfonyl chloride is a reagent that reacts with primary amino groups in both aliphatic and aromatic amines to produce stable blue- or blue-green–fluorescent sulfonamide adducts. It can also be made to react with secondary amines. Dansyl chloride is widely used to modify amino acids; specifically, protein sequencing and amino acid analysis.{{cite book |author=Walker JM |title=Basic Protein and Peptide Protocols |series=Methods Mol. Biol. |volume=32 |pages=321–8 |year=1994 |pmid=7951732 |chapter=The Dansyl Method for Identifying N-Terminal Amino Acids |doi=10.1385/0-89603-268-X:321|isbn=0-89603-268-X }}{{cite book |author=Walker JM |title=Basic Protein and Peptide Protocols |series=Methods Mol. Biol. |volume=32 |pages=329–34 |year=1994 |pmid=7951733 |chapter=The Dansyl-Edman Method for Peptide Sequencing |doi=10.1385/0-89603-268-X:329|isbn=0-89603-268-X }}

Dansyl chloride may also be denoted DNSC. Likewise, a similar derivative, dansyl amide is known as DNSA.

In addition, these protein-DNSC conjugates are sensitive to their immediate environment. This, in combination with their ability to accept energy (as in fluorescence resonance energy transfer) from the amino acid tryptophan, allows this labeling technique to be used in investigating protein folding and dynamics.

The fluorescence of these sulfonamide adducts can be enhanced by adding alpha-cyclodextrin.{{cite journal |vauthors=Kinoshita T, Iinuma F, Tsuji A |title=Microanalysis of proteins and peptides. I. Enhancement of the fluorescence intensity of dansyl amino acids and dansyl proteins in aqueous media and its application to assay of amino acids and proteins |journal=Chem. Pharm. Bull. |volume=22 |issue=10 |pages=2413–20 |year=1974 |pmid=4468087 |doi=10.1248/cpb.22.2413|doi-access=free }} Dansyl chloride is unstable in dimethyl sulfoxide, which should never be used to prepare solutions of the reagent.{{cite journal | last1 = Boyle | first1 = RE | year = 1966 | title = The Reaction of Dimethyl Sulfoxide and 5-Dimethylaminonaphthalene-1-sulfonyl Chloride | journal = The Journal of Organic Chemistry | volume = 31 | issue = 11| pages = 3880–3882 | doi = 10.1021/jo01349a529 }}

The extinction coefficient of dansyl derivatives are important for measuring their concentration in solution. Dansyl chloride is one of the simplest sulfonamide derivatives, so it commonly serves as a starting reagent for the production of other derivatives. Exotic derivatives may have very different extinction coefficients, but others, such as dansyl amide, are similar to dansyl chloride in absorption and fluorescence characteristics. But even for dansyl chloride, there are a variety of extinction coefficient values that have been reported. Some of the values are used to estimate the extent of success in attempts to conjugate the dye to a protein. Other values may be used to determine a precise concentration of a stock solution. See the table below for specific values and their uses.

For all of the studies below, the absorption value is always taken at the maximum that appears between 310 nm and 350 nm. The peak is broad, so the measurement is not very sensitive to wavelength miscalibration of the spectrophotometer, and error due to miscalibration can be avoided by taking the value at the maximum instead of strictly using 330 nm.

class="wikitable" border="1"
Species ! Extinction Coefficient [M−1·cm−1] ! Notes
DNSC-protein | align="center" | 3300{{cite journal | last = Hartley | first = BS |author2=V Massey | title = The active center of chymotrypsin: 1. Labelling with a fluorescent dye | journal = Biochimica et Biophysica Acta | volume = 21 | pages = 58–70 | year = 1956 | pmid = 13363860 | issue = 1 | doi = 10.1016/0006-3002(56)90093-2}} | Use for DNSC-protein conjugates; Used to determine degree of labeling in chymotrypsin and ovalbumin
DNSC | align="center" | 4350{{cite journal | last = Chen | first = RF | title = Dansyl labeled proteins | journal = Analytical Biochemistry | volume = 25 | pages = 412–416 | year = 1968 | pmid = 5704757 | issue = 1 | doi = 10.1016/0003-2697(68)90116-4 }} | In bicarbonate buffer; maximum is shifted to ~315 nm
DNSC | align="center" | 4550{{cite journal | last = Weber | first = G | title = Polarized fluorescence of Protein Conjugates | journal = Biochemical Journal | volume = 51 | pages = 145–155 | year = 1952 | issue = 2 | doi = 10.1042/bj0510145 | pmc = 1197814 | pmid = 14944566 }} | In water; peak shifted to 312 nm
DNSA | align="center" | 4050 | In 60% ethanol; Measured at 329 nm
DNSC | align="center" | 4000{{Cite web | title = Molecular Probes Handbook: Coumarins, Pyrenes and Other Ultraviolet Light–Excitable Fluorophores (Section 1.7) | url = http://www.invitrogen.com/site/us/en/home/References/Molecular-Probes-The-Handbook/Fluorophores-and-Their-Amine-Reactive-Derivatives/Coumarins-Pyrenes-and-Other-Ultraviolet-Light-Excitable-Fluorophores.html | access-date = 12 June 2009}} | Conditions are not given; no reference to the source of this value