quenching a labeling dye - (Nov/17/2004 )

I'm using an Alexa fluor 633 to label a protein that I want to see if it gets into cells. I was wondering if there's a compound (trypan blue?) that I can use to quench any fluorescence that may be due to the dye sticking to the outside of the cell. If there is a good way to do this, please let me know (and if possible provide a literature reference for your suggestion)? Any help would be appreciated Thanks a bunch

Hi cindy
I'm sorry this isn't an answer to your question but I posted a question about labling antibodies with alexa (546) and i wonder if you could help me with some technical problems - i used the molecular probes kit and got only third of the protein i started with (only 0.34 mg/ml from 1 mg/ml). could you give me some advice?
thank you very much
Gilad

The only thing that I can think of as to why you got a lower yield after labeling is because during dialysis it would dilute the protein that you have. I have yet to use the protein that I labeled with the Alexa fluor, let alone check the concentration of it after I dialyzed it. I don't know how much help I can be to you concerning the question you had.....