L-Anilinonaphthalene-8-sulfonic acid

In 2000, the first example of ELP diblock copolymers for reversible stimulus-responsive self-assembly of nanoparticles was reported and their potential use in controlled delivery and release was suggested [87]. Later, these type of diblock copolypeptides were also covalently crossUnked through disulfide bond formation after self-assembly into micellar nanoparticles. In addition, the encapsulation of l-anilinonaphthalene-8-sulfonic acid, a hydrophobic fluorescent dye that fluoresces in hydrophobic enviromnent, was used to investigate the capacity of the micelle for hydrophobic drugs [88]. Fujita et al. replaced the hydrophilic ELP block by a polyaspartic acid chain (D ). They created a set of block copolymers with varying... 

The more sensitive method of Rees et al. (R6) requires about 7 jul plasma per ml dye solution (6 mg l-anilinonaphthalene-8-sulfonic acid per liter phosphate buffer, pH 7.6). The fluorescence intensity of the plasma-dye mixture is measured (activation peak 370 nm, fluorescent peak 485 nm) and the albumin concentration obtained from a standard curve. The dye is stable and has low blank fluorescence a filter fluorimeter is satisfactory for the determination. Bile pigments in excess of about 5 mg/100 ml plasma interfere with the method low results are presumably caused by competition between bilirubin and dye for binding. Bovine albumin has been stated to produce more intense fluorescence with anilinonaphthalene-sulfonate than human albumin (R6). This requires confirmation, since dt... 

Similarly, l-anilinonaphthalene-8-sulfonic acid (ANS) only emits in a hydrophobic environment, being almost completely quenched in aqueous solution. ANS and some other dyes, including 6-(p-toluidinyl)naphthalene-2-sulfo-nate, pyrene, l,6-diphenyl-l,3,5-hexatriene, fluorescein, and rhodamine derivatives attached to long acyl chains or to fatty acids that localize in the cellular membranes were used as probes for hydrophobic sites in proteins, protein folding, imaging of membranes of the cell, and solvent polarity. Pyrene-labeled fatty acids were used to detect the fusion of two membranes. When present in a membrane at sufficiently high concentrations, pyrene excimers (excited-state dimers) are formed that emit at 470 nm. Upon fusion with other membranes, probe concentration decreases, and excimer fluorescence is replaced by monomer fluorescence at 400 nm. This process can be monitored by ratiometric detection of pyrene labels. 

Spectral position and form of fluorescence bands are dependent on the molecular environment (neighbored molecules) and can be used to investigate adsorption, complexation, interaction, or aggregation processes. Special fluorophores like pyrene and l-anilinonaphthalene-8-sulfonic acid (ANS) exhibit dramatic changes of their fluorescence spectra when changing the polarity of their environment and were therefore often applied as fluorescence probes. 

Hydrophobic probes have been widely used to monitor changes in the exposure of aliphatic and aromatic residues of food proteins (Nakai and Li-Chan, 1988). Two of the more popular probes are of the anionic type, l-anilinonaphthalene-8-sulfonic acid (ANS ) and c/5-parinaric acid (CPA). Table 2 shows the hydrophobicity of food proteins monitored by these two probes (Li-Chan, 1991). These probes have high quantum yields of fluorescence in nonpolar environment, and are therefore useful to monitor the accessible or surface hydrophobicity of proteins. However, fluorescence of the ANS probe is influenced by solvents which favor the rigid planar configuration, including aqueous MgCl2 so-... 

Anilinonaphthalene-l-sulfonic Acid Ammonium Salt Reagent... 

Dipping solution Dissolve 100 mg of 8-anilinonaphthalene-l-sulfonic acid ammonium salt in a mixture of 40 ml caustic soda solution (c = 0.1 mol/1) and 57 ml of an aqueous solution containing 21 g citric acid monohydrate and 8 g sodium hydroxide per hter. 

Spray solution Dissolve 100 mg of 8-anilinonaphthalene-l-sulfonic acid ammonium salt in 100 ml water [1]. 

Anilinonaphthalene-l-sulfonic acid ammonium salt, which scarcely fluoresces in aqueous solution, is stimulated to intense fluorescence by long-wavelength UV light (A = 365 run) if it is dissolved in nonpolar solvents or adsorptively bound to nonpolar molecular regions [3]. 

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. 

Collini, M. D Alfonso, L. Molinari, H. Ragona, L. Catalano, M. Baldini, G. Competitive binding of fatty acids and the fluorescent probe 1-8-anilinonaphthalene sulfonate to bovine P-lactoglobulin. Protein Sci. 2003,12 (8), 1596-1603. 

The following fluorescent probes were chosen as substrates N-phenyl-1-naphthylamine (PNA), 1-benzyl-1,4-dihydronicotinamide (BNAH), indole, indolyl-Sracetic acid, 8-anilinonaphthalene-l-sulfonate (ANS), 6-p-toluidinylnaphthalene-2-sulfonate (TNS), and l-dimethylaminonaphthalene-5-sulfonamidoethyltrimethylammonium (DASP). 

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