First, the tyrosine residue in a protein is selectively modified by nitrating
the ortho position of the phenolic ring using tetranitromethane.
Second, the nitrate is then reduced to an amine using sodium dithionite.
Finally, this new aromatic amine can be reacted _AT LOW pH_ with
amine-reactive forms of fluorescent dyes, such as isothiocyanates or sulfonyl
chlorides (succinimidyl esters do NOT work). The lysine and N-terminus amines
do not react well at low pH, so this reaction will be fairly specific for the
tyrosine.
We've got plenty of the amine reactive fluorescent dyes at Molecular Probes.
We have not, unfortunately, got a protocol for this reaction, but here are
some references in which this reaction has been performed: Biochem Int'l 22,
125 (1990) and Biochemistry 18, 3589 (1979).
Here are links on our website that might be helpful:
http://www.probes.com/handbook/ch03-1.html#Alcohols
http://www.probes.com/handbook/tables/tab01-1.html
The second link leads to a table. Look under "other" to find which dyes we
have in isothiocyanate or sulfonyl chloride form.
Hope this helps!
Jill Hendrickson
Molecular Biology Product Manager
Molecular Probes, Inc.
"Jack Simpson, Ph.D." wrote:
> --------------
> Does anyone know if there is such a thing as a fluorescent dye that reacts
> with tyrosine?
> -----------------
>
> I haven't checked specifically for tyrosine, but Molecular Probes
> (http://www.probes.com/) has about everything under the sun in terms of
> fluorescent reagents.
>
> Jack
>
> ~~~~~~~~~~~~~~~~~~
> Jack Simpson, Ph.D.
> Pharmakinetics Laboratories
> 302 West Fayette Street
> Baltimore, MD 21201
> 410-385-4500, ext. 688
> jsimpson@pharmakinetics.com
> http://sx102a.niddk.nih.gov/mass/lnt/simpson.html
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~