Enhanced Diagnostic Tools
A variety of molecular biology assays and purification methods employ biotin to
be used in non radioactive detection method. These biotin-modified oligos bind tightly
to straptavidin, the streptavidin can then be labeled with fluorescent dyes
enzymes or mediate attachment to a solid surface. Biotin can be added to the 5’-
or 3’-ends of an oligo using either a C6 (standard) or TEG (tetra-ethyleneglycol,
15 atom) spacer arm. 5' Biotin-TEG requires purification. Internal biotin modification
can be introduced using a biotin dT base, which also requires additional purification.
Desthiobiotin is a biotin analogue that exhibits lower binding to biotin-binding
proteins such as streptavidin. This biotin analogue is lacking the sulfur group
from the molecule and has a dissociation constant (Kd) several orders of magnitude
less than biotin/streptavidin. As a result, biomolecules containing desthiobiotin
are dissociated from streptavidin simply in the presence of buffered solutions of
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.
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, Contact us