DNase I......how much to use in units? - protein purification issues (Mar/18/2006 )

ive already posted this in my previuos thread but i thought maybe better to post it by itself.... ...so im purifying my protein and want to add DNase.....i have to add 5ug/ml but here i have it in units...so i read on the web and some say use 1 U/ml and others say use 100 units/ml.. ...ive used around 30 units/ml last time but since my purification is not working out im not sure what is going wrong...please tell me how much do you use??? i know it depends on what you want but just some starting point....thankx a lot

Well ...how is it not working out? last time I used it, I added 10 units per ml of sample. The thing is that for some reason, my protein (a small but tough little thing) had a tendency to dissapear with larger quantities. I could never explain why but it definitly did. I just gave up using Dnase anyway.