Fluorescence 6,2- naphthalenesulfonates

In the majority of cases, fluorescent labels and probes, when studied in different liquid solvents, display single-exponential fluorescence decay kinetics. However, when they are bound to proteins, their emission exhibits more complicated, nonexponential character. Thus, two decay components were observed for the complex of 8-anilinonaphthalene-l-sulfonate (1,8-ANS) with phosphorylase(49) as well as for 5-diethylamino-l-naphthalenesulfonic acid (DNS)-labeled dehydrogenases.(50) Three decay components were determined for complexes of 1,8-ANS with low-density lipoproteins.1 51 1 On the basis of only the data on the kinetics of the fluorescence decay, the origin of these multiple decay components (whether they are associated with structural heterogeneity in the ground state or arise due to dynamic processes in the excited state) is difficult to ascertain. 

Extrinsic fluorescence is used whenever the natural fluorescence of a macromolecule is inadequate for accurate fluorescence measurement. In this case, one can attach a fluorescent reporter group by using the reactive isocyanate or isothiocyanate derivatives of fluorescein or rhodamine, two intensely fluorescent molecules. One can covalently also label a protein s a- and e-amino groups with dansyl chloride (/.e., A,A-dimethylaminonaphtha-lenesulfonyl chloride). Another useful reagent is 8-ani-lino-l-naphthalenesulfonic acid (abbreviated ANS). This compound is bound noncovalently by hydrophobic interactions in aqueous solutions, ANS is only very fluorescent, but upon binding within an apolar environment, the quantum yield of ANS becomes about 100 times greater. 

The binding of 8-anilino-l-naphthalenesulfonate (ANS) to ciliary dynein ATPase resulted in a marked increase in the dye s fluorescence intensity, accompanied by a blue shift in the observed fluorescence emission maximum" (Fig. 6). While dynein has 37 3 dye binding... 

Farris, F.J., Weber, G Chiang, C.C., and Paul, I.C. 1978. Preparation, crystalline structure, and spectral properties of the fluorescent probe 4,4 -bis-l-phenylamino-8-naphthalenesulfonate. J. Am. Chem. Soc. 100 4469-4474. 

A simple plot of FJF against [H] from titration of the quenching host into a guest solution should yield a straight line of slope Kn. Common fluorescent guests such as 8-anilino-l-naphthalenesulfonate (ANS, 1.7) may be used to probe complexation ability of various hosts in this way. 

Maity H, Kasturi SR. Interaction of bis(l-anilino-8-naphthalenesulfonate) with yeast hexokinase a steady-state fluorescence study. Journal of Photochemistry and Photobiology B 1998, 47, 190-196. 

Alonso, M.C. and Barcelo, D. Tracing polar benzene- and naphthalenesulfonates in untreated industrial effluents and water treatment works hy ion-pair chromatography-fluorescence and electrospray mass spectrometry. Anal. Chim. Acta 1999, 400, 211-231. 

Gimeno, R. A., Beltran, J. L., Marce, R. M., and Bormll, F., Determination of naphthalenesulfonates in water by online ion-pair SPE and ion-pair liquid chromatography with fast-scanning fluorescence detection, J. Chromatogr. A, 890, 289-294, 2000. 

Fluorescence enhancement of 2-anilinonaphthalene-6-sulfonate (2,6-ANS) in aqueous Na2S04 solution caused by the complexation with CB[6] was reported. In addition, a solid precipitate formed from aqueous Na2S04 solution containing l-anilino-8-naphthalenesulfonate (1,8-ANS) and CB[6] is highly fluorescent. The X-ray crystal structure of the fluorescent solid revealed that 1,8-ANS molecules are clathrated in the lattice of CB[6] molecules with an overall I.8-ANS/CB[6] stoichiometry of2 I.t l... 

In two-phase systems, however, where surfactant and water can partition between a fluid and a liquid phase, significant pressure effects occur. These effects were studied for AOT in ethane and propane by means of the absorption probe pyridine N-oxide and a fluorescence probe, ANS (8-anilino-l-naphthalenesulfonic acid) [20]. The UV absorbance of pyridine A-oxide is related to the interior polarity of reverse micelles, whereas the fluorescence behavior of ANS is an indicator of the freedom of motion of water molecules within reverse micelle water pools. In contrast to the blue-shift behavior of pyridine N-oxide, the emission maximum of ANS increases ( red shift ) as polarity and water motion around the molecule increase. At low pressures the interior polarity, degree of water motion, and absorbance intensity are all low for AOT reverse micelles in the fluid phase because only small amounts of surfactant and water are in solution. As pressure increases, polarity, intensity, and water motion all increase rapidly as large amounts of surfactant and water partition to the fluid phase. The data indicate that the surfactant partitions ahead of the water thus there is a constant increase in size and fluidity of the reverse micelle water pools up to the one-phase point. An example of such behavior is shown in Fig. 4 for AOT in propane with a total fVo of 40. The change in the ANS emission maximum suggests a continuous increase in water mobility, which is due to increasing fVo in the propane phase, up to the one-phase point at 200 bar. 

By analyzing the fast portion of the anisotropy decay it is possible to obtain information about the microviscosity at the location of the probe, and for molecules incorporated at the interface the fluidity of the interfacial layer itself will influence the anisotropy relaxation rate [75]. Another way to obtain information on the water pool microviscosity is given by the application of 8-aniIino-l-naphthalenesulfonic acid (ANS) or Auramin O [76]. For these molecules the quantum yield of fluorescence increases with the microviscosity of the environment. 

Fig.4. Electroluminescence spectrum (solid line) and fluorescence emission spectrum (dotted line) of 4-amino-1-naphthalenesulfonic acid in aqueous solution (10 M).

The total lasalocid-membrane binding reaction is a very sensitive fimction of the membrane polar head group composition Incorporation of dimyristoyl phosphati-dic acid (DMPA) or dimyristoyl phosphatidyl ethanolamine (DMPE) into pure DMPC vesicles reduces the total lasalocid fluorescence relative to that observed in pure DMPC vesicles. Fluorescence lifetime experiments indicate the decrease in fluorescence is not due to reduction of the quantum yield of the bound lasalocid but rather to a reduction in the degree of binding. The sensitivity of total ionophore binding to polar head group composition is similar to that observed for the fluorescent spin probe l-anilino-8-naphthalenesulfonate and indicates... 

Studies have been carried out on the interactions between cyclodextrins and hydrophobic fluorescence probes in water in connection with research on cell adhesion following oligosaccharide/oligosaccharide hydrophobic interactions. While linear oligomers bind 8-anilino-l-naphthalenesulfonate and 6-toluidino-2-naphthalenesuIfonate in 1 1 proportions, the binding constants are smaller than for the corresponding cyclodextrins. ... 

A water-soluble positively charged pillar[6]arene (H5.37) was synthesized by Li and co-workers. H5.37 formed stable host-guest complexes with two anionic naphthalenesulfonate derivatives (G5.123 and G5.124). The association constant determined by fluorescence titration was (2.1 0.3) X10 for G5.122 with two sulfonate moieties (run 152). The K value for G5.122 is 5.5 times higher than that for G5.123 with one sulfonate moiety [run 153, r=(3.8 0.2)xl0 M ] because co-operative electrostatic interactions between two sulfonate anions of G5.122 and cationic pyridinium moieties on the pillar[6]arene rims stabilize the complexation. 

Weber, G., Daniel, E. Cooperative effects in binding by bovine serum albumin. II. The binding of l-anilino-8-naphthalenesulfonate. Polarization of the ligand fluorescence and quenching of protein fluorescence. Biochemistry 5, 1900-1907 (1966)... 

Siano and coworkers [14] report the use of 8-anilino-l-naphthalenesulfonic acid (ANS) as a probe of environment polarity in polyacrylamides containing 1 mole percent n-dodecylacrylamide (estimated from feed ratio) in 2 wt% NaCl. ANS, an amphoteric probe is selectively solubilized at the water-hydrophobe interface. The fluorescence emission maximum is shifted from 520 nm, in aqueous environments to approximately 462 nm in hydrophobic environments [18]. Studies of the polymer described above and a homopolymer of acrylamide were accomplished by varying polymer concentration up to 5000 ppm at constant ANS concentration. In Fig. 2.10 a, a plot of the emission wavelength maximum of ANS vs polymer concentration indicated an increasingly hydro-phobic environment with increasing copolymer concentration. Above approximately 1000 ppm, emission wavelength remained constant, indicating that ANS... 

NH4 or Na 8-anilino-l-naphthalenesulfonate, ANS), and a complex probe (pyrene in the presence of MA-dimethylaniline). The I h ratio (the ratio of the fluorescence intensity of the first and third vibronic peaks of pyrene), which indicates the polarity of the probe environment, increases with increasing FHA concentration and the formation of reversed micelles. The formation of reversed micelles is driven by interactions of TCFE, which are lyophobic with the carboxyl group of the surfactant and favorable with the fluorocarbon chain of the surfactant. The aggregation numbers and the amount of water solubilized in the reversed micelles increase with increasing FHA concentration. 

Although the very existence of CMC of surfactant dissolved in nonpolar has been questioned, the UV absorption and fluorescence emission measurements of AOT-solubilized solubilizates, such as tert-butylphenol, pyrene, and hemi-Mg salt of 8-anilino-l-naphthalenesulfonic acid, in isooctane provided evidence for the existence of CMC at different values of R = [H20]/[A0T] (with R < 3) and CMC value increases with increase in R. The values of CMC, obtained at different temperatures, were used to calculate standard enthalpy of micellization (AH j°) from Equation 1.13 and standard entropy of micellization (AS j ) from Equation 1.14, and these respective values vary from 38.07 to 44.81 kJ mol and 184.60 to 202.60 JK moE with increase in temperature from 20 to 45°C. The positive AH j values arise mainly from the dismantling of hydrated ions in the quasi-lattice of AOT interior. 

FIA of anionics without a phase separation may be based on the quenching effect of surfactants on the fluorescence intensity of 8-anilino-l-naphthalenesulfonic acid coupled with bovine serum albumin (83). Another method of avoiding a phase separation is to use a surfactant-selective electrode. Since interference is a problem, the surfactant-selective electrode approach is best coupled with online concentration with a reversed-phase column. Such a system has been demonstrated for trace analysis of sodium dodecylsulfate (84). 

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