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5'-Tocopherol CE-Phosphoramidite

5'-Tocopherol CE-Phosphoramidite

Phosphoramidite used to incorporate a tocopherol modification at the 5' end of an oligonucleotide.
  • Potential use in aiding cell delivery for nucleic acid therapeutics.
  • When used with a C6 S-S thiol, the tocopherol can be cleaved via the disulphide bridge, for example once the oligo has been delivered to the cell.
  • Has additional applications in the purification of ribozymes and thiol-modified oligos.
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Product information

As with cholesterol modifications, other lipophiles such as tocopherol (vitamin E) have been shown to have potential use in the delivery of oligonucleotides into cells.

Vitamins such as tocopherol are not produced by the target cells, but are used by the latter and therefore vitamins are recognised. They are thought to be internalised by cells only after interaction with a binding protein and therefore have the potential for specific targeting of a cell type.(1)

We have extended our line of lipophilic modifiers to include two products, namely 5'-Tocopherol-CE Phosphoramidite and the analogous 5'-Octyltocopherol-CE Phosphoramidite. These can be used to introduce tocopherol at the 5’ end, either directly on the 5'-OH of the final base or in conjunction with a linker such as C6 S-S thiol. This latter approach enables the tocopherol to be cleaved via the disulphide bridge, for example once the oligo has been delivered to the cell. As a spacer arm is often required for label distancing, the octyl-variant was developed with a “built in” C8 spacer.

As an aside, the hydrophobic nature of tocopherol has also been utilised as a means of improving the purification of ribozymes.(2) We have also demonstrated the use of tocopherol products as a means of allowing an initial purification of thiol-modified oligos with a view to improving the efficiency of a second, e.g. ion-exchange, purification.(3) Available online.


  1. (a) Delivery of oligonucleotides and analogues: The oligonucleotide conjugate-based approach, F. Marlin, P. Simon, T. Saison-Behmoaras and C. Giovannangeli, ChemBioChem., 11, 1493-1500, 2010.; (b) Efficient in vivo delivery of siRNA to the liver by conjugation to alpha-tocopherol, K. Nishina, T. Unno, Y. Uno, T. Kubodera, T. Kanouchi, H. Mizusawa and T. Yokota, Mol. Ther., 16, 734-740, 2008; (c) Resolution of liver cirrhosis using vitamin-A coupled liposomes to deliver siRNA against a collagen- specific chaperone, Y. Sato, K. Murase, J. Kato, M. Kobune, T. Sato, Y. Kawano, R. Takimoto, K. Takada, K. Miyanishi, T. Matsunaga, T. Takayama and Y. Niitsu, Nat. Biotechnol., 26, 431-442, 2008; (d) Attachment of vitamin E derivatives to oligonucleotides during solid-phase synthesis, D. Will and T. Brown, Tet. Letts ., 33, 2729-2732, 1992.
  2. 293 Fast and simple purification of chemically modified hammerhead ribozymes using a lipophilic capture tag, B.S. Sproat, T. Rupp, N. Menhardt, D. Keane, and B. Beijer, Nucleic Acids Research, 27, 1950-1955, 1999.
  3. Oligonucleotide delivery and purification: Tocopherol modification improves product purification and aids delivery into cells, C. McKeen, Gen. Eng. News, 32(3), 22-23, February 1, 2012.

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