For Western blotting, I think that 4G10 is the most sensitive. I think
that the recombinant PY20 from transduction labs works better than the
original PY20 itself. Using the Biacore, I find that for most
phosphotyrosine containing peptides, 4G10 has a greater affinity.
However, I think that individual monoclonal antibodies to P-tyr will show
some sequence preferences, so I use pooled monoclonal antibodies including
Py20, 4G10 and the Ptyr anibodies from SantaCruz. Because I use ECL for
development, I found that I can use extremely small amounts of antibody
(1/1000 - 1/10,000) which are used greater than 10 times. I think that
when you calculate the cost per blot, it is quite reasonable.
Andrey Shaw
