Peptide competition assay - solvent and buffer (Jul/05/2011 )

Hey there,

I want to do a PCA aka Peptide competition assay. My peptide is neutral and I thought to take an organic solvent to help dissolve it. What do you think about methanol or isoprop? Is 0.1% enough? I am considering dissolving it in small amount like 10µL and then filling up with Water...
Also if someone reads this, would be nice if you could suggest the blocking buffer to make the PCA, I guess Milk has to many proteases, what about 5% FCS?

Many thanks
Ivan

Regarding the solvent: the usual solvents are DMSO, DMF or acetonitrile. I prefer the latter, because it is easy to remove by drying in case something goes wrong. There are plenty of web pages dedicated to this. You can take a look here: http://www.thinkpeptides.com/peptidesolubility.html

Concerning blocking: I have never had any trouble using skimmed milk (unless using avdin/streptavidin) or BSA. FCS is also a great blocking agent although not as cheap.

Very helpfull. Thanks
Ivan