ATP quenching

gussak gussak at
Tue Nov 14 07:22:09 EST 2000

ATP is very bad quencher of Trp fluorescence. You thought about quenching because
of a reduced fluorescence intensity. It is mostly probable you got an inner filter
effect: ATP accept a part ot the excitation light intensity and for Trp excitation
you had less. First, try to switch to excitation with higher wavelength (down to
295-300) where absorption of ATP is lower or vanished. Second, take a look, for
example, "Photoluminescence of Solutions" by Parker where you'll find some details
on the inner filter effect.

Good luck

"Jesus M. Sanz" wrote:

> Hi, dear protein-netters!
> I am monitoring ATP binding to a protein, known to bind the ligand, and
> found that the protein tryptophan fluorescence quickly disappears. While
> this could suggest true binding, a control experiment with a protein that
> should
> not bind the ligand also displays fluorescence quenching. I doubt there is
> energy transfer since, as far as I know, ATP does not absorb at the wavelengths
> of tryptophan emmision.
> Is ATP a known quencher of tryptophanyl fluorescence? If so,
> could you pleasesend me a reference about that.
> Thank you very much
> Jesus
> Jesus M. Sanz, Ph.D.
> jmsanz at
> -----------------------------------------------------------------------
> Prof. Jesus M. Sanz
> Centro de Biologia Molecular y Celular -- Universidad Miguel Hernandez
> Edificio TorregaitАn. Avda. Ferrocarril, s/n. ELCHE, 03202-Alicante, SPAIN
> Tel:(34) 966 658 460/474        Fax:(34) 966 658 758
>    E-mail: jmsanz at
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