I want to know the reason of decreasing fluorescence peak intensity with the rise of temperature or with the increase of concentration of denaturant like urea? Please give explanation with proper reference or article.
Thanks in advance.........
If the question was about intrinsic protein fluorescence, then the likely situation is that the fluorescence is coming from one or more buried tryptophan residues in a hydrophobic environment. When the protein is denatured by heat or urea, then the tryptophan residues are exposed to an aqueous environment in which they have lower fluorescence. Not only will you see a decrease in intensity, but you will also see a shift in the emission peak to longer wavelength.
Dynamic quenching is a likely cause of the decrease in fluorescence with increasing temperature or urea concentration, but the precise mechanism depends on the fluorophore and solvent. I suggest you consult the well-known textbook by Joseph Lakowicz, Principles of Fluorescence Spectroscopy.
Here is a technical note on the effect of temperature on rhodamine fluorescence:
https://www.edinst.com/wp-content/uploads/2018/03/TN-P27_FINAL.pdf
I think you are talking about proteins. If the probe gives high fluorescence after binding then denaturation can change the binding properties. Due to that emission intensity will be reduced.
If the question was about intrinsic protein fluorescence, then the likely situation is that the fluorescence is coming from one or more buried tryptophan residues in a hydrophobic environment. When the protein is denatured by heat or urea, then the tryptophan residues are exposed to an aqueous environment in which they have lower fluorescence. Not only will you see a decrease in intensity, but you will also see a shift in the emission peak to longer wavelength.
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