Deoxyribonuclease I (DNase I) is an endonuclease isolated from bovine pancreas that digests double and single stranded DNA into oligo and mononucleotides. Amplification Grade DNase I has been purified to remove RNase activity, and is suitable for eliminating DNA from RNA preparations prior to sensitive applications, such as RT-PCR (Reverse Tranase - Polymerase Chain Reaction). DNase I digests double- and single-stranded DNA into oligo- and mononucleotides. Using the Reaction Buffer provided, DNA is removed from RNA preparations in a 15 minute digestion at room temperature. The DNase I is then inactivated by heating with the Stop Solution. Heating also denatures hairpins in the RNA, so the RNA can be used directly in reverse tranion. No current RNA isolation procedure removes 100% of the DNA. Many commercial DNase I formulations are contaminated with residual RNases. This RNase contamination can destroy or degrade valuable RNA samples prior to reverse tranion. Laboratory comparisons have shown that Sigma′s Amplification Grade DNase I demonstrates lower RNase activity than that from several leading molecular biology product suppliers. | 
