FRAPs

Target of Rapamycin encoded by TORI and TOR2 in yeast mTOR, replaces FRAP, RAFT, RAPT or SEP in mammals... 

Gliszczyhska-Swigl, A. (2006). Antioxidant activity of water soluble vitamins in the TEAC (trolox equivalent antioxidant capacity) and the FRAP (ferric reducing antioxidant power) assays. Food Chemistry, Vol.96, No.l, (May 2006), pp. 131-136, ISSN 0308-8146. 

One of the most popular applications of molecular rotors is the quantitative determination of solvent viscosity (for some examples, see references [18, 23-27] and Sect. 5). Viscosity refers to a bulk property, but molecular rotors change their behavior under the influence of the solvent on the molecular scale. Most commonly, the diffusivity of a fluorophore is related to bulk viscosity through the Debye-Stokes-Einstein relationship where the diffusion constant D is inversely proportional to bulk viscosity rj. Established techniques such as fluorescent recovery after photobleaching (FRAP) and fluorescence anisotropy build on the diffusivity of a fluorophore. However, the relationship between diffusivity on a molecular scale and bulk viscosity is always an approximation, because it does not consider molecular-scale effects such as size differences between fluorophore and solvent, electrostatic interactions, hydrogen bond formation, or a possible anisotropy of the environment. Nonetheless, approaches exist to resolve this conflict between bulk viscosity and apparent microviscosity at the molecular scale. Forster and Hoffmann examined some triphenylamine dyes with TICT characteristics. These dyes are characterized by radiationless relaxation from the TICT state. Forster and Hoffmann found a power-law relationship between quantum yield and solvent viscosity both analytically and experimentally [28]. For a quantitative derivation of the power-law relationship, Forster and Hoffmann define the solvent s microfriction k by applying the Debye-Stokes-Einstein diffusion model (2)... 

FRAP (fluorescence recovery after photo bleaching) analysis was originally developed in the mid-1970s to study the diffusion of biomolecules in living cells (Edidin et al, 1976). Flowever, due to the increased availability of GFP tags and advances in the bleaching capabilities of confocal microscopes, this... 

Figure 3.3 Cartoon and example recovery curve explaining FRAP analysis.

Figure 3-4 FRAP analysis of strain bearing Sui2-GFP PB, pre-bleached image B, bleached image R, recovered image. The bleached focus is marked with an arrow.

These values can be normalized to allow comparison with other FRAP experiments. This involves the generation of a relative fluorescence value expressed as a percentage of the total pre-bleached value. 

Finally, the 14 value for each FRAP experiment can be calculated as the time taken for half of the unbleached proteins to recover in the bleached region using PRISM Version 4 software (GraphPad Software). Comparing the Vi values for the same molecules under different experimental conditions can be used to determine the steps limiting the exchange rate. 

Rabut, Q., and Ellenberg, J. (2005). Photobleaching Techniques to Study Mobility and Molecular Dynamics ofProteins in Living Cells FRAP, iFRAP, and FLIP. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. 

Ferric Reducing Antioxidant Power (FRAP) Assay... 

This assay was first described in 1996 by Benzie and Strain. The FRAP method is based on the ability of phenolics to reduce a ferroin analog, the Fe3+ complex of tripyridyltriazineFe(TPTZ)3+, to the intensely blue colored Fe2+ complex Fe(TPTZ)2+ in acidic (pH 3.6) conditions. In contrast to many other test systems, it does not use any radical. 

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