We describe a procedure allowing extraction of total proteins that
performs efficiently with a large variety of plant tissues, based on
simultaneous precipitation and denaturation with TCA and 2ME in cold
acetone. We also describe protein solubilization prior to IEF, either in
classical rod gels or in IPGs, using two different solutions. The
procedure is easy to carry out. The major caveats are (1) keep samples
at low temperature during extraction, and then (2) manage protein
samples at about 22 to 25?C to avoid urea precipitation.