Plant proteins extraction

[Denis Marc]

I realize for the moment proteins extraction from flower organs grinded in
liquid N2 with a boiling SDS buffer (4% SDS, 5% mercaptoethanol, 5%
sucrose) followed by incubation in an acetone buffer for one hour a -20¡C.

So, question is : Is the acetone step necessary and if it is, what is its
interest?

Thanks in advance
D.M.