5-Me-dC Brancher Phosphoramidite

Catalog: Make Selections to Reveal


A branching monomer is required to construct comb-like oligonucleotide probes. The developers of the comb system from Chiron Corporation evaluated1 several protecting groups for the branch point and chose levulinyl (LEV), which is specifically removed using a reagent containing hydrazine hydrate, acetic acid and pyridine.



  • Coupling: dC Brancher reacts in a manner identical to normal phosphoramidites.
  • Deprotection: Levulinyl Deprotection: The levulinyl protecting group can be selectively removed without cleavage of the oligonucleotide from the CPG by treatment with 0.5 M Hydrazine hydrate in 1:1 pyridine/acetic acid. [Note hydrazine hydrate is a violent poison that is both volatile and readily absorbed through skin] Fit the column with syringes and push the solution back and forth across the column. Let sit for 15 minutes at room temperature. Rinse the column with 1.5 mL of 1:1 pyridine/acetic acid (3x) and then 1.5 mL of ACN (3x). Dry CPG under a stream of argon and proceed with the synthesis of the branching sequence. If a non-branching control is desired, simply deprotect in ammonium hydroxide as required by the nucleobases.
Diluent Anhydrous Acetonitrile
Storage Refrigerated storage, maximum of 2-8°C, dry
Stability 24 hours

Dilution/Coupling Data

The table below show pack size data and, for solutions, dilution and approximate coupling based on normal priming procedures.

ABI 392/394

Catalog # Pack Size Grams/Pack 0.1M Dil. (mL) Approximate Number of Additions
LV40 LV200 40nm 0.2μm 1μm 10μm
10-1018-02 0.25 g .25grams 2.65 75 45 28.13 20.45 15 3.75
10-1018-90 100 µmol .094grams 1 20 12 7.5 5.45 4 1


Catalog # Pack Size Grams/Pack Dilution (mL) Approximate Number of Additions
Molarity 50nm 0.2μm 1μm 15μm
10-1018-02 0.25 g .25grams 3.96 0.07 72.8 45.5 33.09 4.55
10-1018-90 100 µmol .094grams 1.5 0.07 23.6 14.75 10.73 1.48


1 T. Horn, C.A. Chang, and M.S. Urdea, Nucleic Acids Res, 1997, 25, 4842-4849.