DNase I

Frequently Asked Questions

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Features and Benefits

• Suitable for the elimination of DNA from RNA preparations prior to sensitive applications such as RT-PCR
• Minimal RNase activity available
• Optimized 10× reaction buffer and Stop Solution for complete inactivation of DNase I

General description

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 Transcriptase - 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 transcription.

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 transcription. Laboratory comparisons have shown that Sigma′s Amplification Grade DNase I demonstrates lower RNase activity than that from several leading molecular biology product suppliers.

Legal Information

Purchase of this product is accompanied by a limited license for use in the Polymerase Chain Reaction (PCR) process for research purposes only and in conjunction with a thermal cycler whose use in the automated performance of the PCR process is covered by an up-front license fee, either by payment to Applied Biosystems or as purchased, i.e., and authorized thermal cycler.

Unit Definition

One unit completely digests 1 μg of plasmid DNA to oligonucleotides in 10 min. at 37 °C.

Application

Because PCR can detect even a single molecule of DNA, RNA samples should be digested with DNase I before RT-PCR, and parallel reactions should be run without reverse transcriptase to check for amplification of contaminating DNA. 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 transcription.

Many commercial DNase I formulations are contaminated with residual RNases. This RNase contamination can destroy or degrade valuable RNA samples prior to reverse transcription. Laboratory comparisons have shown that Sigma′s Amplification Grade DNase I demonstrates lower RNase activity than that from several leading molecular biology product suppliers (Fig. 1).