Thioflavin-T

Thioflavin, a fluorescent dye, also known as Basic yellow 1 or Methylene yellow . It is a benzothiazole dye. Thioflavin is available in two compounds, listed below as Thioflavin T and Thioflavin S. Both are used as dyes for histology staining (study of tissues) and biophysical studies of protein aggregation and electrophysiology of bacteria.

USES

Thioflavin T (ThT), also called Basic Yellow 1 or CI 49005, is a benzothiazole salt. The dye is widely used to visualize and measure the presence of Amyloids. Amyloids are plaques composed of beta-amyloid found in the brains of patients with Alzheimer’s disease. Formation of amyloid fibrils also results in Prion disease, Parkinson’s disease, type 2 diabetes and has been linked to the development of various diseases in human bodies. When Thioflavin T binds to beta sheets, these amyloid fibrils can be readily detected. Thioflavin T (ThT), though a small molecule, gives strong fluorescence signal at approximately 482 nm when excited at 450 nm upon binding to amyloids.

CHARACTERISTICS

The ThT molecule comprises of a benzylamine and a benzathiole ring connected through a carbon-carbon bond. These two rings rotate freely when the molecule is in solution and the free rotation of these rings reduces any excited state generated by photon excitation. However, when ThT binds to amyloid fibrils, the two rotational planes of the two rings become immobilized and therefore, this molecule can maintain its excited state.

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 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, raising the prospect of false negative results.

PROPERTIES

SPECTRAL PROPERTIES