DNAseI question - (Feb/15/2012 )

Hi all!
I am a very new lab tech with little training, so this question will most likely seem a little silly to most:

I am using a DNA extraction protocol which requires the addition 20 ul of 30ug/ml DNAseI (Roche) to 750ul of template. (then 30min incubation at 37C)

I ordered DNAseI and it came with a concentration of 1u/ul (1000units), and also came with reaction buffer and EDTA.

I've been reading about DNAseI and its use and such, but am still confused as to how get the DNAseI to be a concentration of 30ug/ml from 1u/ul. Am I supposed to be mixing the DNAseI with the reaction buffer to make it a concentration of 30ug/ml?

Like I said, kind of a silly question, but all of this stuff is so new to me!

Thanks for any help.

Why use DNAse on DNA!!!! It will destroy your DNA. Do you mean RNAse instead?

Yes, for DNA extraction you want RNAse. But, here is a link that should help you convert U/ul to ug/ml

http://www.protocol-online.org/biology-forums-2/posts/18064.html

Thanks for your help! It actually is DNAse that I want (very weird, I know). I am extracting an endosymbiotic bacteria from its host, and the DNAse step is required for digesting host cells, before extracting the endosymbiont DNA.

dimitris31b on Thu Feb 16 13:15:37 2012 said:

Not necessarily true, it is common practice to have a DNase step before cell lysis to remove contaminating DNA.