Glen Research biotin phosphoramidites for direct labeling of synthetic oligonucleotides exhibit the following features:
1. All are soluble in acetonitrile at concentrations useful for DNA synthesis.
2. All include a DMT group for cartridge purifications which is essential for the preparation of biotinylated PCR primers because of the potential for cross contamination in HPLC purifications.
3. For the development of diagnostic probes, biotin phosphoramidite is capable of branching to allow multiple biotins to be introduced at the 3’- or 5’-terminus. BiotinTEG Phosphoramidite contains a 15 atom mixed polarity spacer arm based on a triethylene glycol.
4. Protected Biotin Serinol Phosphoramidite and CPG are protected with a t-butylbenzoyl group on the biotin ring. This group is designed to stop any phosphoramidite reactions at this active position in biotin. This protection avoids branching when using nucleophilic activators like DCI. The protecting group is easily removed during oligonucleotide cleavage and deprotection. The BiotinLC versions are similarly protected and should be useful for the synthesis of highly sensitive biotinylated probes.
Biotin-dT can replace dT residues within the oligonucleotide sequence. 5’-Biotin phosphoramidite can be added ONLY ONCE to the 5’-terminus of an oligonucleotide. However, the DMT group on the biotin can be used in RP cartridge and HPLC purification techniques. PC Biotin is a photocleavable 5’-biotin phosphoramidite. BiotinTEG CPG and Protected BiotinLC Serinol CPG are designed for the direct synthesis of oligonucleotides containing biotin at the 3’ terminus.
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 biotin. We offer desthiobiotinTEG phosphoramidite and the corresponding CPG.