can RIPA buffer use to prepare nuclear protein? - (Jul/17/2004 )

i want nuclear protein and cytoplast protein.

are there any good suggestin?
thank you

please help me!
RIPA:
50mM Tris-cl
1%NP40
0.5 % deoxycholic acid
0.1% SDS
1mM EDTA
150mM NaCl

after 19000*g,15min, i get supernatant,is the supernatant include the whole nucleus protein?