The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Thermodynamics of the quenching of tyrosyl fluorescence by dithiothreitol.

Tyrosyl fluorescence quenching by oxidized dithiothreitol (DTTo) in N-acetyl-L-tyrosine N'-methylamide, and native bovine pancreatic ribonuclease A and its reduced, S-methylated form, in aqueous solution is studied at pH 3. 0. From the temperature dependence of the fluorescence quenching, it is demonstrated that the mechanism of the quenching process is probably static (formation of a complex), and not dynamic (collisional), in origin. Although other quenching mechanisms cannot be ruled out, our proposition that the quenching of tyrosyl fluorescence in these molecules is due to the formation of a complex between the tyrosyl moieties and DTTo is consistent with previously reported evidence indicating a strong tendency for aromatics to complex with various disulfide-containing compounds. The strength of binding is approximately the same for these three tyrosine-containing compounds, indicating that the microenvironments of their tyrosyl residues may be similar. With 1 M as the reference standard state, the following average thermodynamic parameters are established for the complexation (at 298 K): delta G0 = -3.32 kcal/ mol, delta H0 = -1.1 kcal/ mol, and delta S0 = 7.4 eu. The large positive value of delta S0 suggests that hydrophobic interactions may play an important role in the stabilization of such tyrosyl-disulfide complexes; the negative value of delta H0 suggests that polar interactions may also contribute to the formation of these complexes. Some possible implications with regard to protein-folding studies are discussed.[1]


  1. Thermodynamics of the quenching of tyrosyl fluorescence by dithiothreitol. Swadesh, J.K., Mui, P.W., Scheraga, H.A. Biochemistry (1987) [Pubmed]
WikiGenes - Universities