I agree with all previous answers, but wanted to point out that downstream applications should be considered as well. TE contains EDTA which can inhibit some enzymatic reactions (ligation, blunting, PCR) if present in sufficient concentration. TE is a good choice to resuspend high-concentration stock DNA (like 100uM PCR primers) because you know A) it will "protect" your DNA long-term by buffering and chelation, and B) you can dilute high concentration TE stocks to working concentrations with H2O later, simultaneously diluting TE/EDTA concentration.

Dear Priya,

TE buffer for DNA storage contains EDTA which is inhibiting DNases (since it's chelating Ca2, Mg2,...) and therefor protects the DNA from degradation. In case you have some important DNA samples you should go for TE buffer. If you "just" have samples from cells etc. that are easily reproducible or you don't need them for longer time, you can just use water!

The pH of TE buffer is slightly basic however water have slightly acidic pH. This basic pH of TE buffer makes DNA more soluble and EDTA helps to protect from the DNase as Ariane Eberhardt said.

TE buffer is also preferable over H2O to store the DNA samples.

good luck

 I would recommend using typically Tris-EDTA buffer or TE-Buffer, as the pH and the conditions stabilize the DNA for a longer time and the EDTA inhibits DNase from degrading the DNA as explained by Eberhardt and Vats

In addition to everything explained above, according to "Molecular Cell Biology" by Lodish et al. 2002),  positive ions at proper concentrations prevent separation of DNA strands, which are negatively-charged because of phosphate groups. At extreme pHs or absence of ions, bases repel each other and hydrogen bonds are destabilized. If the DNA molecules are large enough, there should be too many hydrogen bonds for the strands to disassociate. In some protocols, EDTA concentration is lowered to 0.1 mM instead of 1 mM to prevent inhibition of further reactions due to chealating effect of EDTA.

I agree with all previous answers, but wanted to point out that downstream applications should be considered as well. TE contains EDTA which can inhibit some enzymatic reactions (ligation, blunting, PCR) if present in sufficient concentration. TE is a good choice to resuspend high-concentration stock DNA (like 100uM PCR primers) because you know A) it will "protect" your DNA long-term by buffering and chelation, and B) you can dilute high concentration TE stocks to working concentrations with H2O later, simultaneously diluting TE/EDTA concentration.

Dear Priya, in a simpler scientific and logical way we can explain this as water is mainly un-buffered and due to the unequal sharing of its electrons it behaves more acidic than basic so ultimately the amount of negative charge is more on water, while the DNA is also acidic in nature and has dominating negative charges, so when we put DNA into water for storage it can undergo acid hydrolysis with time. It is like you are storing an acid with an acid. That is why DNA tends to be safer with any mild alkali buffer, (as they are positively charged) from pH 8-8.5, so DNA dissolves best at alkaline pH, but be careful that the EDTA component of such buffers should be from 01.-0.5 mM to avoid any hindrance later in downstream applications you want to use this DNA. But, since water and DNA both are polar molecules so still they can be dissolved easily in each other, but definitely with some harm on your DNA.

TE buffer is (T, It came from Tris-HCl ; that maintain pH=8 and osmosis, E, It came from Ethylene diamine tetra acetic acid, abbreviation is (EDTA); that prevent DNase from analysis DNA , In other word, It links with Mg++ necessary for the effectiveness of an DNase enzyme. I hope that the answer is obvious :) 

As i remember when i did DNA extraction, if you want to storage your DNA sample for longer time, you should dilute it on TE buffer because it will make the DNA more stable rather than using sterile dH2O. 

Yes, TE for storage at 4-8°C, dH20 only if you store your samples at -20°C.

No, TE does NOT inhibit PCR !

We always use TE buffer as the last step in DNA extraction, we dissolve it in TE buffer for storage prior to PCR. TE buffer stabilizes DNA and prevent its degradation. Sure TE buffer do not inhibit PCR. 

Dear Dirk and Nibras how do u unequivocally say TE buffer doesn't inhibit PCR when theoretically it is quite possible at higher concentrations of TE buffer . Although DNA will be more stable in TE buffer than dH2O. But downstream processes  also need to be taken into consideration.

DNA polymerase is a metalloenzyme with Mg2+ its cofacter. . The active site of DNA polymerase binds two metal ions. One Mg2+ stabilizes the reactive state of the bound dNTP, and a second Mg2+ takes an active role in catalysis as postulated in the two metal ion mechanism (Steitz, 1998). Mg2+ shields the negatively charged phosphate groups of the nucleotide triphosphate to avoid repulsion of the nucleophile during catalysis( Jencks, 1987). Mg2+ may also be involved in increasing the reactivity of the attacked phosphorus by withdrawing electrons and stabilizing the leaving phosphate.

 At higher concs.  EDTA ,in TE buffer , will  chelate more Mg2+ ions . If the Mg2+ gets below critical conc., PCR will be affected and if very low  Mg2+ is availabe PCR will be almost completely inhibited .

hope this helps 

Dear Sheikh,

the concentration we talk about is 10mM Tris-Cl and 1mM EDTA for TE. With this conc I never had any problems with inhibition in 25 years. But, anything is possible with PCR.

Dear Dirk, in the first answer u didn't specify the concentration . Now ur point is more accurate and  acceptable .

best wishes

Sheikh Gulfam

Dear Dirk, considering a concentration of 1.5mM divalent cations in the PCR reaction and if you dilute your sample in TE 20 times in the final volume of the PCR, then you will still have 50uM EDTA in the reaction. This is unlikely to have consequences on a regular PCR, however, it could still lead to some variation in more sensitive applications like qPCR (it happened to me to observe some drop in slope once testing primers efficiency which was likely due to accidentally diluting a TE resuspended DNA in Tris-only buffer), although I haven't tested it properly with some controls.

I agree for the above reflection, that the role of Tris EDTA (TE) buffer in DNA extraction is solubilize DNA by protecting it from the degradation. the chemical composition gives the TE buffer very stable than H2O since, Tris: is the common PH buffer while EDTA: is the molecule that chelates positively charged molecules Mg+2 and other sourced from cell during the lysis process, in did so inhibit the enzymatic reaction in the process. that H2O can't give this, need further investigation in my experiment noted that by putting DNA pellet with& without TE in +4oc significant variation in the DNA amount

TE buffer keep dna from break down ,also its ph is suitable more than d.water.