Spectral Properties - Fluorescence

Excitadon at 295 nm yields a fluorescence spectrum with a peak equal to 331 nm (Fig. 3.3). The position of the peak is typical for proteins containing tryptophan residues in a hydrophobic env ronment and results from the contribution of both polar and hydrophobic Trp residues. 

I lgiire 8.25. E.xcitation anisotropy spectrum of ai-acid glycoprotein recorded ai -45°C in glycerol/pliosphate buffer. 

In order to put into evidence the Trp residues thet participate in the emission of the protein, quenching resolved emission with cesium were first performed. When a protein contains two classes of intrin fluoropliore. one at the surface of the protein and the second embedded in the protein matrix, fluorescence intensify quenching with cesium allows obtaining the spectra of these two classes. A selective quenching implies that addition of quencher induces a decrease in the fluorescence observables (intensity, anisotropy and lifetime) of the accessible class. At high quencher concentration the remaining observables measured will reflect essentially those of the embedded fluorophore residues. 

Dynamic fluorescence quenching is analyzed by the Stern-Volmer equation  

Knowing fa and fb along the emission spectrum will allow us to draw the spectrum of each class of fluorophore. 

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Fluorescence spectral properties. The absorption and emission spectra should be in the visible-wavelength range to avoid autofluorescence from biological systems... 

Module 1, Determination of Chemical and Structural Information on the Sample. The task of Module 1 is to provide non-chromato-graphic data for analytes prior to specification of the chromatographic method. Data bases have been developed for pK values of organic molecules, isoelectric points of proteins, and fluorescence spectral properties of organic molecules. 

Malicka, J., et al. (2003) Fluorescence spectral properties of cyanine dye-labelled DNA oligomers on surfaces coated with silver particles. Anal Biochem 317 136-46. 

The electronic absorption spectra as well as the fluorescence spectral properties of BPHTs have been investigated by several research groups [16-24]. The spectroscopic results, obtained in several organic solvents of different polarities, in water and in CD media, provided important information on... 

Excited Singlet State and Fluorescence Spectral Properties... 

The fluorescence spectral properties of BPHTs and three methyl derivatives were also studied in a predominantly aqueous medium (water/ethanol 99 1, v/v) in the presence and absence of CDs (HP- -CD or P-CD), and in ethanol [18-22]. The excitation and emission spectra presented a similar shape in the various media. The excitation spectra appeared in the 320-340 nm region for all compounds under study, whereas for 10- and 11-MeBPHTs, a strong band located at 276-279 nm and a weaker one around 340-350 nm were obtained in all media. For unsubstituted BPHT, 9-, 10- and 11-MeBPHT, slight blue shifts (3-15 nm) occurred in a predominantly aqueous medium (water/ethanol 99 1, v/v) mixture relative to ethanol [18-21]... 

Metalloporphyrins and related compounds continue to attract attention as photosensitizers and as building blocks for construction of artificial lightharvesting arrays. The photophysical properties of several structurally modified porphyrins have been measured with a view to identifying new sensitizers for use in photodynamic therapy. The triplet state properties of porphyrins adsorbed onto the outer surface of vesicles have been describedand the fluorescence spectral properties of some amphiphilic porphyrins have been recorded. Similar studies have been carried out with halogenated tetraar-... 

Nakashima K, Akiyama S, Tsukamoto S, Imai K. Synthesis of pyrimido [5,4-d] pyrimidine derivatives and their ultraviolet absorption and fluorescence spectral properties. Dye Pigment 1990 12 21. 

Akiyama S, Akimoto H, Nakatsuji S, Nakashima K. Development and application of organic reagents for analysis VI. Synthesis and fluorescence spectral properties of 2-(4-substituted phenyl)benzofiirans. Bull Chem Soc Jpn 1985 58 2192-96. 

Of the many papers on the fluorescence spectral properties of complex polyatomic molecules published during the past year, a few may be singled out as meriting special attention. There have been several additions to the growing list of molecules exhibiting relatively easily observable fluorescence from second excited singlet states. The observations this year have been largely confined to... 

The phosphorescence and fluorescence spectra of compound (23) have been recorded <89CBi 119>. The electronic and fluorescence spectra have been measured for azuleno[l,2-f>]furan (144), which is an iso-/7-electron system of benz[a]azulene and presents anomalous fluorescence from the second excited singlet state, as does azulene <87SA(A)1377). Fluorescence spectral properties of a series of 2-(4-substituted phenyl)benzofurans have been investigated to determine their applicability as organic reagents for analysis <85bcj2192>. 

Melittin is an ideal protein to illustrate the effects of structure on the fluorescence spectral properties. Each monomer contains a singly tryptophan residue and no tyrosine residues. The X-ray structure of the tetrameric form shows that the tryptophan residues are buried in a non-polar pocket and are not directly exposed to the aqueous phase. 

Table 3.2. Fluorescence Spectral Properties of Commcmiy Used Extrinsic Prot s ...

A nundier d reviews have summarized tiie fluorescence spectral properties of prottins. Reviews of protein fluorescence frequently begin with the spectral properties of nuilti-tiypcophan protdns. which have been studied since the 1950s. The emisaon maximum and quantum... 

Shinkai and coworkers reported cationic polythiophene 11 obtained by the direct oxidative polymerization of the tetraalkylammonium salt of a thiophene monomer (Scheme 16.3). The molecular weight of the polymer was not determined however, its absorption and fluorescence spectral properties were consistent with the polythiophene backbone structure. Schanze and coworkers reported the use of a direct polymerization method to prepare the cationic poly(arylene ethy-nylene) 8 that features a backbone that alternates thienylene-ethynylene and phenylene-ethynylene repeat units (Scheme 16.4). Thus, polymerization of the cationic tetraalkylammonium substituted 1,4-diiodobenzene with 2,5-diethynyl-thiophene via a Sonogashira coupling protocol catalyzed by Pd(0)/Cu(I) catalyst in aqueous/DMF afforded 8. The resulting polymer was purified by aqueous dialysis using an 8 kD molecular weight cutoff membrane. As with the previous examples, the molecular weight of the cationic CPE was not determined. 

Solutions of the retinol-RBP complex are highly fluorescent. The fluorescence properties of human RBP have been studied in detail (Peterson and Rask, 1971 Goodman and Leslie, 1972), and information is also available about the fluorescence spectral properties of RBP isolated from several other species. Retinol bound to RBP has uncorrected peak excitation and emission maxima of 334 and 463 nm, respectively. The relative fluorescence intensity of retinol bound to RBP (in aqueous solution) is an order of magnitude greater than that of retinol in solution in any one of a variety of organic solvents (Goodman and Leslie, 1972 Futterman et al., 1975). In addition, for retinol bound to RBP, the... 

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