adding and adding DNase ...still viscous... - (Apr/19/2006 )

this is about DNase again... ...i read over and over web pages about how much in units should I use DNase for cell lysis and at last i decided that for 600 mg of E coli (dissolved in 1.5 ml of lysis buffer) i will use 40 ul of 2units/ul DNase....but it didnt work... ...i add another 10ul and wait at RT for 30 minutes but again no change, solution still viscous... ...the things is that its company (wako) never replies to me and there is no magnesium in its buffer and no other buffer to use....so im asking here in the lab and they dont know ... ....should I just keep adding DNase till the solution is no more viscous?? but there is not much in the vial.... ...what do you think i should do???

hi
sonication will derade DNA but no proteins. It helped my colleague. She put her proteins in the loadin buffer and sonicated 30'' twice. Little viscous, but loaded !
so i think thatyou may sonicate for DNA shear.

DNAse requires Mg2+ and, I believe, CaCl2. I do my DNAse digestions in 25 mM Mg2+ and 5 mM CaCl2...