Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Texas Red: Difference between pages

{{About|the dye}}

| Verifiedfields = changed

| verifiedrevid = 476993717

| CASNo_Ref = {{cascite|changed|??}}

| CASNo = 82354-19-6

| SMILES = C1CC2=C3C(=C4C(=C2)C(=C5C=C6CCC[N+]7=C6C(=C5O4)CCC7)C8=C(C=C(C=C8)S(=O)(=O)Cl)S(=O)(=O)[O-])CCCN3C1

[[File:TexasRed.jpg|200px|thumb|The solution in the bottle (15 ml) has 0.009 mg/ml Texas Red in [[Dimethylformamide|DMF]]. Bulk powder is dark purple.]]

'''Texas Red''' or '''sulforhodamine 101 acid chloride''' is a red [[fluorescent]] [[dye]], used in [[histology]] for [[staining]] cell specimens, for sorting cells with [[fluorescent-activated cell sorting]] machines, in [[fluorescence microscopy]] applications, and in [[immunohistochemistry]].<ref>{{cite journal |author=Titus JA |author2=Haugland R |author3=Sharrow SO |author4=Segal DM |title=Texas Red, a hydrophilic, red-emitting fluorophore for use with fluorescein in dual parameter flow microfluorometric and fluorescence microscopic studies |journal=J. Immunol. Methods |volume=50 |issue=2 |pages=193–204 |date=1982 |pmid=6806389 |doi=10.1016/0022-1759(82)90225-3}}</ref><ref>[http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Product_Information_Sheet/1/s3388pis.pdf Sulforhodamine 101 acid chloride] Sigma-Aldrich product information</ref>

Texas Red fluoresces at about 615&nbsp;nm, and the peak of its absorption spectrum is at 589&nbsp;nm. The powder is dark purple. Solutions can be excited by a [[dye laser]] tuned to 595-605&nbsp;nm, or less efficiently a [[krypton laser]] at 567&nbsp;nm. The absorption extinction coefficient at 596&nbsp;nm is about 85,000 M⁻¹cm⁻¹.

The compound is usually a mixture of two monosulfonyl chlorides, i.e., as pictured, or with the SO₃ and SO₂Cl groups exchanged. It can be used as a marker of proteins, with which it easily forms [[Conjugated system|conjugate]]s via the [[sulfonyl chloride]] (SO₂Cl) group. In water, the [[sulfonyl chloride]] group of unreacted Texas Red molecules [[hydrolysis|hydrolyses]] to [[sulfonate]] and the molecule becomes the very water-soluble [[sulforhodamine 101]] which is easy to wash out selectively. This is one of the advantages of conjugating with Texas Red vs. using a rhodamine-[[isothiocyanate]] for conjugation.

A protein with the Texas Red chromophore attached can then itself act as a fluorescent labeling agent; an [[antibody]] with a fluorescent marker attached will bind to a specific [[antigen]] and then show the location of the antigens as shining spots when irradiated. It is relatively bright, and therefore can be used to detect even weakly expressed [[antigen]]s. Other molecules can be labeled by Texas Red as well, e.g., various toxins. The dye dissolves very well in water as well as other polar solvents, e.g., [[Dimethylformamide]], [[acetonitrile]].

Texas Red, attached to a strand of DNA or RNA, can be used in Fluorescent ''in situ'' Hybridisation (FISH) as a [[molecular beacon]] for highlighting specific sequences of [[DNA]]. Texas Red can be linked with another [[fluorophore]]. A tandem conjugate of Texas Red with R-[[phycoerythrin]] ('''PE-Texas Red''') is often used.

Fluorophores, like Texas Red, are commonly used in [[molecular biology]] techniques like quantitative [[RT-PCR]] and cellular [[assay]]s.<ref>{{cite journal |author=Ahmad AI |author2=Ghasemi JB |title=New FRET primers for quantitative real-time PCR |journal=Anal Bioanal Chem |volume=387 |issue=8 |pages=2737–43 |date=2007 |pmid=17308892 |doi=10.1007/s00216-007-1123-4|s2cid=39968312 }}</ref>

Newer [[rhodamine]] derivatives, such as [[Alexa (fluor)|Alexa 594]] and [[DyLight Fluor|DyLight 594]], have been tailored to match the excitation and emission spectra of Texas Red and are used in various chemical and biological applications where greater [[Photobleaching|photostability]] or higher fluorescence intensity are needed.

==References==

{{reflist}}

[[Category:Staining dyes]]

[[Category:Rhodamine dyes]]

[[Category:Triarylmethane dyes]]

[[Category:Nitrogen heterocycles]]

[[Category:Oxygen heterocycles]]

[[Category:Heterocyclic compounds with 7 or more rings]]