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|Section2= |Section3= }} Thioflavins are dyes used for histology staining and biophysical studies of protein aggregation. They are also used in biophysical studies of the electrophysiology of bacteria.〔Prindle et al. ''Nature'' 2015. doi:10.1038/nature15709〕 ==Thioflavin T== Thioflavin T (Basic Yellow 1 or CI 49005) is a benzothiazole salt obtained by the methylation of dehydrothiotoluidine with methanol in the presence of hydrochloric acid. The dye is widely used to visualize and quantify the presence of misfolded protein aggregates called amyloid, both ''in vitro'' and ''in vivo'' (e.g., plaques composed of amyloid beta found in the brains of Alzheimer's disease patients). When it binds to beta sheet-rich structures, such as those in amyloid aggregates, the dye displays enhanced fluorescence and a characteristic red shift of its emission spectrum.〔H. LeVine III, ''Methods in Enzymology.'' 309, 274 (1999)〕 This change in fluorescent behavior can be caused by many factors that affect the excited state charge distribution of thioflavin T, including binding to a rigid, highly-ordered amyloid structure, or to specific chemical interactions with a protein.〔L.S. Wolfe ''et al.'', (Protein-induced photophysical changes to the amyloid indicator dye thioflavin T ) ''Proc Natl Acad Sci USA'' 107, 16863 (2010)〕 Thioflavin T fluorescence is often used as a diagnostic of amyloid structure, but it is not perfectly specific for amyloid. Depending on the particular protein and experimental conditions, thioflavin T may〔 or may not〔H. LeVine III, ''Prot. Sci.'' 2, 404 (1993); H. LeVine III, ''Amyloid Int. J. Exp. Clin. Invest.'' 2, 1 (1995)〕 undergo a spectroscopic change upon binding to precursor monomers, small oligomers, unaggregated material with a high beta sheet content, or even alpha helix-rich proteins. Conversely, some amyloid fibers do not affect thioflavin T fluorescence,〔A.L. Cloe ''et al.'', (The Japanese Mutant Aβ (ΔE22-Aβ1−39) Forms Fibrils Instantaneously, with Low-Thioflavin T Fluorescence: Seeding of Wild-Type Aβ1−40 into Atypical Fibrils by ΔE22-Aβ1−39 ) ''Biochemistry'' 50, 2026 (2011)〕 raising the prospect of false negative results. In adult ''C. elegans'', exposure to thioflavin T results "in a profoundly extended lifespan and slowed aging" at some levels, but decreased lifespan at higher levels.〔Alavez S. et al, (2011). (Amyloid-binding compounds maintain protein homeostasis during ageing and extend lifespan ) ''Nature''〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Thioflavin」の詳細全文を読む スポンサード リンク
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