how to do deproteinization for DNA samples? - (Jul/21/2008 )
Hello all
PLZ i want ur help
after i have extracted DNA and add TE buffer during incubation i found that there a white suspension in the tube so i would greatly appreciate helping me to get out those protein from the sample.
Best regards
A phenol:chloroform extraction is one way...
unfortuanately i don't have phenol in my lab.
is there any solution else?
Are you sure they are proteins??
A good point by Madrius -- why don't you tell us what exactly you did as an extraction method, and where you saw the white precipitate. If your solution is ethanolic, the "white suspension" could be your DNA...
That sounds a bit silly but what if you spin it at max speed and transfer the supernatant in a new tube?
When I do midi/maxi prep of plasmid with a common kit, I get some white precipitates after resuspending the DNA pellet in buffer. I spin it at max speed, 4 degree for 10 min and transfer the supernantant in a new tube. The 260/280 and 260/230 ratios seem in acceptable range.
i use salting out method - digest protein with proteinase k and sds then add saturated NaCl aE fterthat i take supernatant and precipitate DNA using cold ethanol. in some samples the dna threads not appear white like light brownish colour after washing in 70% alc and drying i add TE buffer and incubate at 37 C for 2 hours then i found the solution is like a jelly and white in colour.
now i add more TE to the tube and leave it overnight.
now i add more TE to the tube and leave it overnight.
What is the purpose of the 37 C incubation in TE?
to dissolve DNA.
I don't know exactly what you're doing, and there may be reasons why you do it the way you do, but I'd be inclined to dissolve my DNA in a larger volume of slightly basic (say pH 8.0 -- acids, like DNA, dissolve better in bases) TE, rather than incubating it for hours trying to get it to dissolve...