I recently ordered some RNase A from Roche that came in a dried powder form. I went online to get instructions on how to Prepare RNAse A, only to find out that this product has no instructions!
Sigma has a package insert online for their RNase A. They suggest:
1) Preparing a 10mg/mL solution in 10mM sodium acetate, pH 5.2
2) Heat to 100 C for 15 minutes.
3) Allow to come to room temperature.
4) Add .1 Volume of 1 M Tris-HCl, pH 7.4
5) Aliquot and store at -20 C
This is how I decided to prepare my RNase A. I later read that RNase A can withstand temperatures up to 100 C - sure hope heating it at 100 C didn't denature it!
Now to remove RNA from a DNA solution (already isolated using a kit):
1) Added stock RNase A to a working concentration of 10 ug/mL - my sample was in 1x TE.
2) Incubated at 50 C for 20 minutes.
3) allowed to come to room temperature
4) Stored at 4 C.
Today I'm going to restrict my DNA sample - will RNase A affect the restriction enzymes? I plan to do a chloroform/phenol extraction afterward..