On Wed, 4 Oct 1995, Ellen Lumpkin wrote:
 
> I am looking for a small, polar fluorophore that is not sensitive to Ca,
> pH, membrane potential, etc. to coinject with fluo-3 into cells.  I am
> currently using sulforhodamine 101, but it seems to quench fluo-3
> fluorescence very effectively.
 
You Could try carboxy SNARF from molecular probes.  Although it is pH
sensitive, it has an isosbestic point at 610nm and is often loaded
alongside FLUO-3 and its fluorescence is ratioed to control for loading,
leaching and bleaching- but it doesn't have to be if you don't want ratio it.
(try looking at "Improved method forfor Measuring Intracellular Ca++ With
Fluo-3" G.T. Rijkers et al Cytometry 11,923 (1990))
 
 
> reading through James Pawley's "Handbook...", I noticed a fluorophore
> called PerCP that excites at 488 and fluoresces at 680.  Is this product
> commercially available?
 
Yes it is, but it doesn't meet you smallness criterion, (PerCP=Peridinyl
ChloroPhyll), I think it's available from Becton-Dickinson but only in
conjugated form (to antibody)
 
> I want to stress that I am not collecting data for ratios, so I do not want
> to use a second Ca-sensitive fluorophore.>
 
Carboxy SNARF still fits even though it usually is ratioed (to itself for
pH or to FLUO-3 for Ca), since at 610 nm its fluorescence is pH and Ca++
independent.
 
 
Hope this helps
 
Ray