To degrade DNA requires metal ions. The EDTA in TE binds the metal ions and so slows down the degradation. The higher pH of the Tris also slws down DNA degradation.
It is commonly used in molecular biology. The purpose of TE buffer is to solubilize DNA or RNA, while protecting it from degradation.source: http://en.wikipedia.org/wiki/TE_buffer
TE buffer protect DNA or RNA from degradation. "TE" is derived from its components: Tris (Interact with the lipopolysaccharide and lyes the cell membrane and prevent other cells from attacking), and...