Biotin design

However, if we can design some sophisticated routes to generate carbanion equivalents in the active site of the enzyme, carboxylation reaction might be possible. In fact, acetyl-CoA is carboxylated with the aid of biotin in the biosynthetic pathway of long-chain fatty acids. 

MTS-ATF-biotin and MTS-ATF-LC-biotin are trifunctional crosslinkers similar in design to sulfo-SBED discussed previously, but in addition to the biotin handle, they contain a... 

Figure 11.1 The basic design of a biotinylation reagent includes the bicyclic rings and valeric acid side chain of D-biotin at one end and a reactive group to couple with target groups at the other end. Spacer groups may be included in the design to extend the biotin group away from modified molecules, thus ensuring better interaction capability with avidin or streptavidin probes.

Figure 16.1 The general design of an ICAT reagent consists of a biotinylation compound with a spacer arm containing stable isotope substitutions. The reactive group is used to label proteins or peptides at particular functional groups and the biotin affinity tag is used to isolate labeled molecules using immobilized (strept)avidin.

Hydrophilic short biotin-PEG tags also have found their way into the design of multifunctional crosslinkers to study protein structures by mass spec. Fujii et al. (2004) developed a homobifunctional NHS ester crosslinker that in addition has a PEG-biotin handle (Figure 18.1). The reagent actually is a trifunctional compound similar to the biotinylated PIR compound... 

Figure 27.9 Biotin-ll-dUTP is perhaps the most popular nucleotide derivative used for enzymatic biotinylation of oligonucleotides. The 11 designation refers to the number of atoms in its spacer arm.

The design of the photoprobe is based on structure-activity relationship (SAR) studies if available. Ideally the photoprobe should be bioactive over the same range as its parent compound. The next step is to synthesize the bioactive photoprobe in radiolabeled form. Similarly, non-radioactive labels (primarily biotin) can also be attached via a linker arm [18]. 

No phosphitylation of biotin nitrogen N2 was observed under these reaction conditions. The phosphoroamidite formed was designed for direct use in automated DNA synthesized using standard phosphoroamidite chemistry to introduce a photocleavable biotin label on the 5 -terminal phosphate of synthetic oligonucleosides. 

---