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 10�L 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