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| Identifiers | |
|---|---|
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.245.455 |
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| Properties | |
| C31H29ClN2O6S2 | |
| Molar mass | 625.15 g·mol−1 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Texas Red orsulforhodamine 101 acid chloride is a redfluorescentdye, used inhistology forstaining cell specimens, for sorting cells withfluorescent-activated cell sorting machines, influorescence microscopy applications, and inimmunohistochemistry.[1][2]Texas Red fluoresces at about 615 nm, and the peak of its absorption spectrum is at 589 nm. The powder is dark purple. Solutions can be excited by adye laser tuned to 595-605 nm, or less efficiently akrypton laser at 567 nm. The absorption extinction coefficient at 596 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 formsconjugates via thesulfonyl chloride (SO2Cl) group. In water, thesulfonyl chloride group of unreacted Texas Red moleculeshydrolyses tosulfonate and the molecule becomes the very water-solublesulforhodamine 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; anantibody with a fluorescent marker attached will bind to a specificantigen 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 expressedantigens. 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 Fluorescentin situ Hybridisation (FISH) as amolecular beacon for highlighting specific sequences ofDNA. Texas Red can be linked with anotherfluorophore. A tandem conjugate of Texas Red with R-phycoerythrin (PE-Texas Red) is often used.
Fluorophores, like Texas Red, are commonly used inmolecular biology techniques like quantitativeRT-PCR and cellularassays.[3]
Newerrhodamine derivatives, such asAlexa 594 andDyLight 594, have been tailored to match the excitation and emission spectra of Texas Red and are used in various chemical and biological applications where greaterphotostability or higher fluorescence intensity are needed.
