The most simple way to isolate protein from leaf tissue is to crush it in liquid nitrogen to make it powder and then add 50 mM phosphate buffer, pH 7.2 to make a paste (1ml / gram of leaf tissue), in chilled conditions. Later, centrifuge the paste at 9,000 rpm for 10-15 mins and collect the supernatant. Its all crude protein. 

Hello, maybe your question should be a little bit more precise. Are you looking for a protocol? Do you want to isolate cytoplasmic or membrane-bound proteins?

Maybe you can have a look at this: http://tools.lifetechnologies.com/content/sfs/productnotes/F_Trizol%20and%20Trizol%20LS-041018-RD-TL-HL0506021.pdf

Good luck

Thank you Thomas Dobrenel

Actually am looking for cytoplasmic protein isolation

and did you find something interesting in the link I sent you? Or I can try to find another protocol.

ya, this method is something different from other conventional methods. But this protocol is based on Trizol  reagent.

Please let me know if you find out any  simple conventional protocol for total protein extraction or cytoplasmic protein extraction.

Thank you very much Dear Thomas Dobrenel 

The most simple way to isolate protein from leaf tissue is to crush it in liquid nitrogen to make it powder and then add 50 mM phosphate buffer, pH 7.2 to make a paste (1ml / gram of leaf tissue), in chilled conditions. Later, centrifuge the paste at 9,000 rpm for 10-15 mins and collect the supernatant. Its all crude protein.