DNA extraction basics - (Oct/08/2005 )

Im a newbie in the wonderful world of biology research and I have a really basic question on the DNA extraction: why do we use a alkaline buffer (EDTA.. etc) during the lysis of the cell, aiming to release the DNA ?

Thx in advance

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Dear friend,

In a typical alkaline lysis buffer (Tris, EDTA, SDS buffer):
- Tris: adjust pH of buffer to 8.0. Bassically, you can use any inorganic salt (NaOH) to do so, but it will only stay there by using Tris of Hepes.
- EDTA: chelates divalent metals (primarily magnesium and calcium). Removal of these cations destabilizes the cell membrane. It also inhibits DNases and RNase as well.
- SDS: pops holes in the cell membranes.

With this combination, DNA can be release from cell.

Best regards

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