That depends on composition of the buffer. E.g. simple Tris will extract only soluble proteins, while RIPA contains 1% Triton and 1% deoxycholate, so it should completely dissolve all membranes and extract all proteins.

That depends on composition of the buffer. E.g. simple Tris will extract only soluble proteins, while RIPA contains 1% Triton and 1% deoxycholate, so it should completely dissolve all membranes and extract all proteins.

You must choose buffers and their componets depending on purpose of experiment

if protein-protein interaction avoid using ionic detergents

also if you want to just make total protein to check expression you can even dissolve cells directly in 2x sds sample buffer.

so be specific about usage based on that one can suggest buffers.

Check out this website for differences on buffers and types of proteins they will extract.

http://www.abcam.com/ps/pdf/protocols/wb-beginner.pdf