6-p-Toluidino-2-naphthalenesulfonic acid, potassium salt (TNS-K+)

Product ID: M0720

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Fluorescent probe for conformational studies and for use in quantitation of hydrophobic proteins. This potassium salt is more water soluble than the free acid, M0704.

Protein folding, conformational changes or other processes that modify the exposure of the probe to water can be monitored using this environmentally sensitive dye. TNS is a fluorescent probe useful for measuring conformational changes and quantitative studies of protein hydrophobicity. It is practically nonfluorescent in water, becoming fluorescent when bound to membranes (q.y. ~0.27) or hydrophobic domains of proteins (q.y. ~0.72). The fluorescence is also enhanced by cyclodextrins, permitting a sensitive method for separating and analyzing cyclodextrins with capillary electrophoresis. This potassium salt of TNS is more water soluble than the free acid, M0704.

Technical Data
SKU M0720
CAS Number 32752-10-6
Unit Size 100mg
Absorption 318nm
Emission Wavelength 443
Extinction 26
Detection Method Fluorescence
Molecular Formula C₁₇H₁₄NSO₃K
Molecular Weight 351.46
Soluble In DMSO, DMF, H2O
Storage Conditions 2-8C, Desiccated, Protect From Light
Notes Ex=318nm

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References and Citations


  • Lampe JN, Fernandez C, Nath A, Atkins WM. (2008) "Nile Red is a fluorescent allosteric substrate of cytochrome P450 3A4." Biochemistry. 47(2):509-16.
  • Nath A, Fernández C, Lampe JN, Atkins WM. (2008) "Spectral resolution of a second binding site for Nile Red on cytochrome P4503A4." Arch Biochem Biophys. 474(1):198-204.
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  • QaDan M, Spyres LM, Ballard JD. (2000) "pH-Induced conformational changes in Clostridium difficile toxin B." Infect. Immun. 68 2470-2474.
  • Batlle N, Carbonell JV, Sendra JM. (2000) "Determination of depolymerization kinetics of amylose, amylopectin, and soluble starch by aspergillus oryzae alpha-amylase using a fluorimetric 2-p-toluidinylnaphthalene-6-sulfonate/flow-injection analysis system." Biotechnol Bioeng 70544-552.
  • Frank J, et al. (1997) "Kinetics and equilibrium binding of the dyes TNS and RH 421 to ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)." J. Chem. Soc. Faraday Trans. 932379.
  • Jones M, Keenan RW, Horowitz P. (1982) "Use of 6-p-toluidino-2-naphthalenesulfonic acid to quantitate lipids after thin-layer chromatography." J. Chromatogr. 237522.
  • McClure WO, Edelman GM. (1966) "Fluorescent probes for conformational states of proteins. I. Mechanism of fluorescence of 2-p-toluidinylnaphthalene-6-sulfonate, a hydrophobic probe" Biochemistry 5(6)1908-1919.
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