Avidin-biotin complexation

Heitzmann, H. and Richards, E. M. (1974) Use of the biotin-avidin complex for specific staining of biological membranes in electron microscopy. Proc. Natl. Acad. Sci. USA 71, 3537-3541. 

Fig. 18.1. (A) Schematic presentation of the biotin-avidin complex with detailed configuration of biotin and surrounding polar residues. (B) Detailed (top) and simplified (bottom) representations of the complication possibilities of biotin and avidin. (C) Structure of an electropolymerizable biotin derivative and schematic presentation of an electropolymerized polypyrrole film bearing biotin groups on its surface. All three-dimensional representations of avidin have been generated using the program VMD [70] and subsequently rendered with PovRay.

A very recent paper details the biomolecular functionalization of a polypyrrole nanowire. ZnSe/CdSe quantum dots were functionalized with avidin and these quantum dots were incorporated into a polypyrrole nanowire during its electrochemical formation between two electrodes 100 nm apart [32], Biotin with a DNA strand attached was shown to modulate the conductivity of the avidin nanowire, but not an unfunctionalized polypyrrole nanowire fabricated similarly. Presumably, the DNA-biotin-avidin complex would also be sensitive to changes in the hybridization state of the DNA. 

Though biotin-avidin complexation has been used widely to isolate specific targets, it is notorious for generating false-positive identifications. To mle out the possibility that our results were an artifact we set out to find the OP-labeled peptide. We reasoned that convincing proof for OP labeling required identification of the labeled peptide and the labeled amino acid. 

Figure 8-15. Immunoprecipitation of C-biotin-avidin complex with avidin-immune serum. (A) A constant amount of serum obtained from a rabbit immunized with avidin was added to increasing quantities of C-biotin-avidin complex. (B) An identical amount of control serum, obtained before immunization, was used in place of the immune serum.

Prepare a C-biotin-avidin complex by dissolving 10 mg avidin and 7.5 fxc C-biotin in sufficient 0.85% saline solution to yield a final... 

Plot the amounts of radioactivity observed in each of the 16 pellets and supernatant solutions as a function of the volume of C-biotin-avidin complex added to that test tube. Such a plot is shown in Figure 8-15. 

It influences fat metabolism, decarboxylation and carbon dioxide fixation, and deamination of some amino acids. It is closely related metabolically to pantothenic acid and folic acid. A biotin deficiency may be induced by ingestion of avidin, a raw-egg protein, because of the formation of a nonabsorbable biotin-avidin complex. Biotin is synthesized in the intestinal tract of humans therefore, normally it is not essential in the diet. 

Fig. 4 Time domain THz pulses obtained by measuring the difference signal between biotin and biotin-avidin conjugated agarose (a), biotin and biotin-avidin complexes without beads (b),...

On the other hand, the local removal of an attached biotin/avidin complex has been accomplished by generating hydroxide ions electrochemically. Investigating the mechanism of the reaction between hydroxide ions and the various constituents of the system led the authors to conclude that the reaction occurring at the electrode was a hydrolysis of all the amide bonds involved in the immobilization reaction. 

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].)...

Figure 17. Computer-predicted structure of the pyrenylalanine-linked biotin-avidin monomer complex. The structure was generated by attaching an L-l-pyrenylalanine unit to the X-ray crystallographic structure of the biotin-avidin complex, followed by optimization of the rotational angles (0, ij/, Xu Xz) of the pyrenylalanine unit. Aromatic carbons of the pyrenyl group and those of indole groups are emphasized.

Beyond electrostatic and hydrophobic forces, the heterocoagulation process could be controlled by secondary molecular interactions. We will briefly highlight with some examples the hydrogen bonding, ji-ti interactions, and speciflc molecular interactions obtained from complementary DNA strands, and biotin-avidin complexation. 

Figure 12 Scheme of the structure of a virtual multilayered heterostructure made from all kinds of molecules or particles that have been shown to be usable for ESA. Components (a) boladications and other multipolar molecules (b) lipid bilayers (c) polyelectrolytes (d) dendrimers (e) DNA (p proteins (g) viruses (h) inorganic sheets (i) inorganic nanopartides (j) latex nanospheres (k) LB interlayers (I) biotin/avidin complex. (Adapted from Y.M. Lvov and G. Decher. Crystallogr. R p. 39 628,1994. With permission.)... 

Carbon fiber None Note g 40-5000 The biotin/avidin complex was used to obtain a surface layer of HRP 9... 

Additional studies have shown that [ Cjbiotin injected i.p. into rats as the avidin complex was excreted much more slowly than the free vitamin. Nevertheless, the biotin-avidin complex was dissociated in vivo and the released biotin excreted and metabolized to sulfoxides and bisnorbiotin. That liver has the capacity to cause such dissociation and metabolism was demonstrated. The rate and extent of excretion of bisnorbiotin is essentially the same as for biotin. The more water-soluble tetranorbiotin, both d- and J-sulfoxides of biotin, and biotin sulfone were excreted even more rapidly. 

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