precipitation of protein (PI=9.5) but not DNA - I need protein free sample for DNA quantification (Aug/14/2008 )
I need to quantify DNA in a suspention of non-soluble protein (PI=9.5).
I tried to centrifuge the protein but the DNA seems to participate as well.
I can dissolve the protein at high pH (>13).
Does anyone know of a method for precipitation of protein at high pH without precipitating the DNA as well ?
I will appreciate any sugestion.
Can you do a Phenol:Chloroform extraction ?
Add 1 vol NaCl 5M, incubate on ice for 5 min then centrifuge. Add the supernatant to a clean tube (don't touch the pellet) and add 2.5 vol of cold alcohol (abs etoh or isopropanol) and 0.5 vol NaAc (3M), mix by invertion (shoul see the DNA "strings" incubate -20C O/N or -80C 1h. Centrifuge, discard supernatant, add 1 mL 70% etoh, dislodge pellet (dont resuspend) centrifuge again, discard supernatant. Air dry or use a vac drier the DNA (don't over dry). resuspend the pellet with 1X TE.