Pyrene fluorescent probe, incorporation into

Yamana et al. [67] used bis-pyrene-labeled DNA aptamer for detection of ATP. The pyrene excimer was incorporated into several nucleotide positions. Addition of ATP resulted in an increase in fluorescence only for aptamers labeled by fluorescence probe between residues that were responsible for ATP binding. Using this sensor it was possible to detect ATP with mmol/L sensitivity. 

Measurement of the influence of different micellar environments on proton transfer from excited states of 3-hydroxyflavone allows estimates to be made of micelle concentrations from measurement of the tautomer emission yield. Proton transfer reactions of benzimidazole excited singlet states have also been studied in ionic micelles. Magnetic fields are found to affect the behaviour of radicals generated by the photodissociation of benzil in micellar media. The starburst dendrites which are formed by anionic macromolecules in interaction with both anionic and cationic surfactants have been examined by pyrene fluorescence. Benzo[k]fluoranthrene fluorescence has served as a probe of the effects of metal salts on bile salt aggregation. The incorporation and distribution of benzoquinone into liposomes containing amphilic Zn(II) porphyrin has been followed by its effect on the quenching of the excited state °. A comparison of the photochromism of spirobenzpyran derivatives in unilamellar surfactant vesicles and solvent cast surfactant films has also been reported. ... 

Kumar et reported the synthesis of pyrene-modified nucleotides and their effects in secondary nucleic acid structures. Pyrene was attached to the 5 -position of thymidine (26a) or to the 2 -position of 2 -deojgairidine via a triazolomethylene linker (26b), or via a triazole linker (26c). These nucleosides were converted into their phosphoramidites and then incorporated into oligonucleotides, and analysed by thermal stability and fluorescence studies. These experiments indicated that these oligonucleotides can act as specific recognition probes. 

On the other hand, pyrenyl-L-alanine 184 has also been used as a conformational probe in the characterization of an artificial 4-a-helix bundle protein.11,121 The 53-residue peptide 186 incorporating one residue of 184 in each of two different helical segments was synthesized by solid-phase synthesis using a segment condensation strategy and the oxime resin. Boc-pyrenyl-L-alanine 191 was coupled just like any other amino acid by the BOP/HOBt method in DMF. CD and fluorescence studies demonstrated that the two pyrene groups were in close proximity forming an excimer complex, which is possible only when the polypeptide chain folds into a 4-a-helix bundle structure. 

Other solubilization and partitioning phenomena are important, both within the context of microemulsions and in the absence of added immiscible solvent. In regular micellar solutions, micelles promote the solubility of many compounds otherwise insoluble in water. The amount of chemical component solubilized in a micellar solution will, typically, be much smaller than can be accommodated in microemulsion formation, such as when only a few molecules per micelle are solubilized. Such limited solubilization is nevertheless quite useful. The incorporation of minor quantities of pyrene and related optical probes into micelles are a key to the use of fluorescence depolarization in quantifying micellar aggregation numbers and micellar microviscosities [48]. Micellar solubilization makes it possible to measure acid-base or electrochemical properties of compounds otherwise insoluble in aqueous solution. Micellar solubilization facilitates micellar catalysis (see section C2.3.101 and emulsion polymerization (see section C2.3.12T On the other hand, there are untoward effects of micellar solubilization in practical applications of surfactants. When one has a multiphase... 

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