Tryptophan Fluorescence

November 18, 2011

When studying biological reactions using microplate readers, a signal is needed for detection to determine what is going on in each well.

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Dr EJ Dell
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Microplate readers cannot just “see” DNA, proteins, or cells and usually a fluorescent or luminescent tag is necessary to illuminate the biological activity. Nature however has provided researchers with such a protein tag, that is the amino acid tryptophan. Under certain conditions tryptophan can fluorescence and be quantified. The Application Notes listed below show how several different laboratories have taken advantage of this fluorescent property of tryptophan to study the activation of heterotrimeric G proteins as well as the binding of antibodies.


  1. Using intrinsic tryptophan fluorescence to measure heterotrimeric G-protein activation
  2. Investigation of the stereoselectivity of an anti-amino acid antibody utilizing tryptophan fluorescence