Fluorescent assay for

Analyses for the Saxitoxins. Early methods for analysis of the saxitoxins evolved from those used for toxin isolation and purification. The principal landmarks in the development of preparative separation techniques for the saxitoxins were 1) the employment of carboxylate cation exchange resins by Schantz et al. (82) 2) the use of the polyacrylamide gel Bio-Gel P2 by Buckley and by Shimizu (5,78) and 3) the development by Buckley of an effective TLC system, including a new solvent mixture and a new visualization technique (83). The solvent mixture, designated by Buckley as "E", remains the best for general resolution of the saxitoxins. The visualization method, oxidation of the saxitoxins on silica gel TLC plates to fluorescent degradation products with hydrogen peroxide and heat, is an adaptation of the Bates and Rapoport fluorescence assay for saxitoxin in solution. Curiously, while peroxide oxidation in solution provides little or no response for the N-l-hydroxy saxitoxins, peroxide spray on TLC plates is a sensitive test for all saxitoxin derivatives with the C-12 gemdiol intact. 

Kroes-Nijboer A, Lubbersen YS, Venema P, van der Linden E (2009) Thioflavin T fluorescence assay for [beta]-lactoglobulin fibrils hindered by DAPH. J Struct Biol 165(3) 140... 

Neelakandan PP, Hariharan M, Ramaiah D (2006) A supramolecular ON-OFF-ON fluorescence assay for selective recognition of GTP. J Am Chem Soc 128 11334-11335... 

Medium-throughput assay 500- 10.000 Imaging and Fluorescent assays for activities evaluation [43]... 

McIntyre, J.C. and Sleight, R.G., 1991, Fluorescence assay for phospholipid membrane asymmetry. Biochemistry, 30 11819-11827. 

Aboul-Enein and Al-Duraibi (1998) employed dansyl chloride in a fluorescence assay for PUT, SP, SPD, and their acetylated derivatives by ion-pair reverse-phase chromatography. This assay could be applied to the separation of free and acetylated polyamines in biological samples. Dansyl chloride has also been used as the fluorescence reagent in the determination of polyamines in urine by Molins-Legua and colleagues (1999). Derivatization was carried out within the C18 cartridges that were used during the SPE extraction procedure. Recoveries were 80-95% for all four polyamines analyzed and the hmit of detection was 10 ng/ml. 

Stack and Gray have described a convenient, continuously recording, fluorescent assay for rabbit collagenase and gelatinase based on the hydroly-... 

Collazo, E., Couture, J.F., Bulfer, S. and Trievel, R.C. (2005) A coupled fluorescent assay for histone methyltransferases. Analytical Biochemistry, 342, 86-92. 

The presence of a-methyldopa and its metabolites in the urine reduces the diagnostic value of urinary catecholamine measurements as an indicator of pheochro-mocytoma, since these substances interfere with the fluorescence assay for catecholamines. 

QM Wang, RB Johnson, JD Cohen, GT Voy, JM Richardson, LN Jungheim. Development of a continuous fluorescence assay for rhinovirus-14 3C protease using synthetic peptides. Antiviral Chem Chemother 8 303-310, 1997. 

We specifically chose the reaction between anthracene and maleimide (Figure 5.3.1) for a number of reasons. Most importantly, we assumed that the completely different overall geometry of reactants and products would facilitate enrichment of catalysts that are capable of multiple turnovers. Anthracene is planar, in contrast with the 120° angles between the different rings in the Diels-Alder product. A ligand that can bind to anthracene should, therefore, not be able to bind to the product except after extensive refolding. The availability of sensitive UV absorbance and fluorescence assays for anthracene was another practical reason to choose this reaction. 

Fluorescence Assay for Analytes with Native Fluorescence... 

The described method is a typical HPLC fluorescence assay for drug level determination for toxicokinetic purposes. However, the conditions of sample extraction, the choice of the internal standard substance, the choice of the HPLC stationary and mobile phase and the combination of excitation and emission wavelength has to be adjusted specifically to the properties of the analytes. Particularly, the lipophilicity, the pKa value and the pH stability of the analytes have to be considered. 

Waddleton, D. et al. 2002. Development of a time-resolved fluorescent assay for measuring tyrosine-phospho-rylated proteins in cells. Anal. Biochem. 309, 150-157. 

Ferrer, M. et al. 2003 Miniaturizable homogeneous time-resolved fluorescence assay for carboxypeptidase B activity. Anal. Biochem. 317. 94-98. 

Trusca, D. and D. Bramhill. 2002. Fluorescent assay for polymerization of purified bacterial FtsZ cell-division protein. Anal. Biochem. 307, 322-329. 

Figure 16. Number of compounds inhibiting cathepsin D by concentration of inhibitor. Result of high through-put fluorescence assay for cathepsin D...

Fluorescence assays for biotransformations are an indispensable tool for enzyme engineering and the daily practice of enzyme studies. Fiuorogenic substrates are particularly useful as general probes for enzyme classes that can be used in routine screening and activity checking. However, they cannot replace the authentic substrate in cases where an optimization towards a particular biotransformation is desired. In such cases an indirect fiuorogenic assay or an instrumental assay may be required in order to follow the reaction. A variety of fluorescence assays for enzymes still remain to be discovered and the development of new enzyme assays... 

Pais, J.E., Bowers, K.E., Stoddard, A.K., and Fierke, C.A. (2005). A continuous fluorescent assay for protein prenyltransferases measuring diphosphate release. Anal Biochem 345 302-311. 

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