Problems with Qiagen Maxipreps?

[Reese Bolinger]

Hi:

I haven't done many transfections, but have done a lot of Qiagen maxis.  
I know that, for reasons unclear to me, that using home-made buffers, 
even if made with the best quality reagents never seem to give DNA of 
quite the same quality as that I get using the buffers straight from 
Qiagen (based on OD 260/80 ratios), though they work fine for all of the 
techniques that I routinely use.  

More related to your question:  I received a flyer from Qiagen a short 
while ago referring to the detrimental effect of endotoxin on 
transfection efficiency, which could be part of the problem.  Qiagen has 
recently started carrying a line of purification buffers that are 
certified endotoxin free specifically for purifying plasmid DNAs for 
transfection.

Hope this helps and good luck!

			                                               Reese