The DADE linker is a pre-activated carboxyl linker for the 5’ terminus of an oligonucleotide. It was designed for the solid phase conjugation of amine bearing compounds directly to an oligonucleotide, although it has other applications. If it is left in its activated form when the oligonucleotide is deprotected, it will react with the prevalent nucleophile in the solution (ammonia in ammonium hydroxide forming the amide, the hydroxyl in sodium hydroxide forming carboxylic acid, etc.). Its major advantage is that it can be used for solid phase conjugation to amine bearing compounds, negating the need for costly succinimidyl esters. This allows high throughput screening, and the reuse of compound that did not conjugate in the first reaction. It also allows for the use of large excesses that will enhance conjugation efficiencies, and reduce cost. It has many other applications.

 Yes, click here to view the reagents still sold through TriLink. All of our other DNA synthesis reagents are now sold through Glen Research.

The main difference is the protecting group. The MMT linker is protected with a monomethoxytrityl group and the TFA linker is protected with a trifluoroacetate group. The MMT linker is acid labile, whereas the TFA group is base labile. MMT is the best choice when you want a pure amino labeled oligonucleotide. Since the MMT group is more nonpolar, it acts as a purification handle on reverse phase HPLC just like the DMT group. The TFA protected linker is better for crude conjugations where the oligonucleotide is used after deprotection. As a word of caution, remember to exchange the ammonia for another salt prior to conjugation since excess ammonia will severely reduce the efficiency of many conjugations.