Cholesterol and cholesteryl modifiers are used to facilitate the permeation of cell
membranes. These oligos can be used in conjunction with lipofectin, or liposome
incorporation of the oligo.
The cholesterol type modifications are available to tag either the 5' or 3' end
of the oligo. Cholesterol is available for labeling the 3' end of oligo and cholesteryl
is available for labeling the 5' end. As with the 3' modifier, labeling occurs during
the course of synthesis. The 5' cholesteryl modification results in a mixture of
modified and unmodified oligos. As a consequence, two bands are generally visible
on a gel photo after 5' labeling. One band represents a full-length unmodified oligo,
and the other band represents a full-length modified oligo. In general, cholesterol-modified
oligos can be difficult to dissolve in aqueous solutions. In most cases a freeze/thaw
cycle may help to get the oligo into solution. We recommend keeping cholesterol-modified
oligos in solution and best purified using rpHPLC.
Desalt or cartridge (RP1) purification is acceptable for most common phosphoramidite
modifiers. However, additional purification is strongly recommended for modifiers
that require NHS-ester chemistry to conjugate a dye through an amine linker such
as Molecular Probes dyes.
Minimum Guarantee Purified Yield
Due to the chemistry of many modifications, yield will be approximately 40 - 60
% less than a standard oligo. Please see our yield chart for details.
Every oligo synthesized is strictly controlled for quality by using either MALDI-TOF
mass spectrometry or polyacrylamide gel electrophoresis (PAGE) analysis. Final yields
are determined using UV absorbance at OD260 In addition, we perform QC
methods tailored to specific modifications, such as OD ratio measurement where appropriate.
For additional information, please Contact us.