Western blot using blood plasma - (Aug/16/2013 )

If I wish to examine phosphoprotein levels in plasma samples using Western blot, do I just use the samples directly for the experiment like protein lysates? Are there any preparations or taboos I should be aware of?

you may find that you have to deplete albumin to get a good look at all of the phosphoproteins.

Will the use of albumin depletion kit do the job? A reference paper warned that there might be non-specific loss which may affect the analysis.

there are some albumin depletion kits that are very specific for albumin (such as this one from sigma).

This is very helpful!! Thank you!!

If I performed immunoprecipitation before western blot, will it decrease the non-specific signals? if so, can I directly use the plasma for pull-down? The depletion of albumin should be done BEFORE the immunoprecipitation, right?