Avidin complex with biotinylated

Figure 22.21 Antibodies may be conjugated to liposomes using an indirect approach incorporating a (strept)avidin-biotin system. Biotinylated liposomes may be complexed with biotinylated antibodies using (strept)avidin as a bridging molecule or may be complexed with an antibody-(strept)avidin conjugate.

These examples are part of a broader design scheme to combine catalytic metal complexes with a protein as chiral scaffold to obtain a hybrid catalyst combining the catalytic potential of the metal complex with the enantioselectivity and evolvability of the protein host [11]. One of the first examples of such systems combined a biotinylated rhodium complex with avidin to obtain an enantioselective hydrogenation catalyst [28]. Most significantly, it has been shovm that mutation-based improvements of enantioselectivity are possible in these hybrid catalysts as for enzymes (Figure 3.7) [29]. 

As conjugates, complexes from biotinylated hapten and strep-tavidin maybe used. In that case perform the detection with avidin-biotinylated hapten because avidin and streptavidin do not cross-react. 

Biotin-avidin interaction. The cellular delivery capacity of several CPPs has been proven using complexes of biotinylated peptides with labeled avidin or strep-tavidin (23,27,37). Avidin could also serve as a scaffold for the assembly of molecules to be delivered into cells using biotinylated CPPs to facilitate the uptake process. 

Chen VJ, Wold F. Neoglycoproteins preparation and properties of 49. complexes of biotinylated asparagine-oligosaccharides with avidin... 

Useofavidin-biotin technology in immunoaffinity chromatography can lead to improved performance of the affinity column, which translates both into yields of the target material and stability of the column (1,2). The presence of free biotin-binding sites of the avidin-4 esin allows secondary interaction with biotinylated antibody or its complexes with avi-din that may have leaked from the affinity resin. 

Using the characteristic of a high-affinity complex between avidin and biotin, biotinylated antibodies have wide applications in various immunochemical assays, especially where signal amplification is required. A method is described here for the biotinylation of immunoglobulins. The procedure utilizes water-soluble succinimidyl ester of biotin that reacts with primary amines of the lysine residues or the amino terminus on the antibody to form amide bonds. The method is simple and specific and results in stable conjugates retaining full immunologic activity. 

Figure 6.8 The scheme used by Pantano and Kuhr to attach glutamate dehydrogenase to the surface of a carbon fiber. Step 1, after electrochemical oxidation of the fiber to produce surface oxygen functionalities, a diamine is attached to the surface using carbodiimide coupling. Step 2, biotin is attached to the other end of the diamine. Step 3, the bound biotin is reacted with avidin to form a biotin-avidin complex attached to the carbon surface. Step 4, biotinylated enzyme is complexed to the avidin to complete construction of the enzyme modified carbon fiber surface. (Adapted from [27].)...

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