Larsen et al. suggest adding it after dissolving the washed and dried DNA pellet in TE:

http://www.ncbi.nlm.nih.gov/pubmed/18770603

Alternatively, I think adding it after the proteinase K digestion, before adding the NaCl would be a good place to do it if you wanted to avoid protein in your final sample. If you do it there I would let the samples cool to room temperature, add the RNase, and incubate for a few minutes at room temperature.

Best wishes,

Brian Weinrick

Before proteinase inactivation and after DNA solubilization in TE buffer...

It's necessary to add before or after proteinase K enzyme, there is no difference if you add before or after

Dear All,

Thanks for your answers, I really appreciate!

Davis