Tris-EDTA buffer, pH 8.0, is recommended for long-term storage of DNA. How does it work?

Tris-EDTA buffer at pH 8.0 is designed to provide a stable environment for DNA during long-term storage. The high pH in the Tris buffer helps stabilize the DNA by inhibiting acid-catalyzed hydrolysis, which can degrade nucleic acids over time. Acidic conditions can lead to the cleavage of the phosphodiester bonds in DNA, ultimately resulting in strand breaks. By maintaining a pH around 8.0, the buffer ensures that the DNA is less susceptible to these harmful hydrolytic reactions.

In addition to pH stabilization, EDTA plays a crucial role in protecting the integrity of the DNA. EDTA is a chelating agent that binds divalent metal ions, such as magnesium and calcium, which are essential cofactors for many nucleases—enzymes that can degrade DNA. By sequestering these metal ions, EDTA effectively inhibits the activity of nucleases, thereby preserving the DNA from being broken down during storage.

This combination of maintaining a suitable pH and using EDTA to prevent nuclease activity makes Tris-EDTA buffer an optimal choice for long-term DNA storage. This understanding highlights the importance of both pH and the role of chelating agents in