Glen Report 35-26: Technical Snippets

Why is 5-Me-C the only cytosine version in certain backbones?

We typically receive this question as it pertains to our Locked Nucleic Acid (LA) and MOE monomers. LA and MOE oligonucleotides were developed for therapeutic applications. In the case of LA, both 5-Me-C LNA and C LNA oligonucleotides have been studied in the literature. However, 5-Me-C offers certain benefits, including reduced immune response and stronger base pairing. In some product lines, 5-methylated U is also offered instead of the unmethylated version.

Relevant products:

Bz-5-Me-C-LA-CE Phosphoramidite (10-2011)

Bz-5-Me-C-LA-CPG (20-2511)

5-Me-C-2′-MOE-Phosphoramidite (10-3211)


Is it possible to desalt short oligonucleotides (≤10mer) using Glen Gel-PakTM columns? 

Glen Gel-PakTM columns are not compatible for desalting short oligonucleotides (≤10mer). The desalting concept for these columns relies on size exclusion chromatography. Molecules above the exclusion limit of the resin elute early from the column whereas molecules below the exclusion limit are retained in the matrix longer, effecting the separation between large
and small molecules. Small oligonucleotides (≤10mer) are small enough to enter the matrix, preventing the proper desalting of the short oligonucleotide. Alternatively, our Glen-PakTM cartridges are efficiently able to purify both short and long oligonucleotides. The principle of the Glen-PakTM cartridge purification relies on the DMT-ON oligonucleotides. As long as the short oligos are DMT-ON then Glen-PakTM cartridges should be able to purify them following the DMT-ON purification procedure. There is no need for further desalting after the Glen-PakTM purifications.

Relevant products:

Glen Gel-Pak 1.0 Desalting Column (61-5010)

Glen Gel-Pak 2.5 Desalting Column (61-5025)

Glen Gel-Pak 0.2 Desalting Column (61-5002)