Biotin and avidin

Salmain, M., Fischer-Durand, N., Cavalier L., Rudolf, B., Zakrzewski, J., and Jaouen, G. (2002) Transition metal-carbonyl labeling of biotin and avidin for use in solid-phase carbonyl metallo immunoassay (CMIA). Bioconjugate Cbem. 13, 693-698. 

X. Mao, J.H. Jiang, J.W. Chen, Y. Huang, G.L. Shen, and R.Q. Yu, Cyclic accumulation of nanoparticles a new strategy for electrochemical immunoassay based on the reversible reaction between dethio-biotin and avidin. Anal. Chim. Acta 557, 159-163 (2006). 

The determination of the lysozyme activity using the bacterial electrode (see p. 139) can also be used for immuno-analysis of biotine and avidine. The determination is based on the inhibition reaction of avidine with the biotine-lysozyme conjugate. After the reaction, the conjugate is no longer capable of dissolving the cell wall of the bacteria. The determination of biotine is similar [15]. 

The strong bond between biotin and avidin/streptavidin can only be released by extreme and often denaturating conditions. For a reversible binding based on this complex, o-desthiobiotin can be used instead of biotin (see Fig. 13). This conjugate can be separated at room temperature by exposure to an excess amount of biotin, respectively desthiobiotin [42]. 

Only the force-field energy term associated with interactions between the biotin and avidin fragments remains. This is added to the differential solvation free energies and differential thermal terms to determine the full binding free energy. 

The avidin-biotin complex (ABC) method and the streptavidin-biotin (SAB) method are more sensitive than the peroxidase-antiperoxidase (PAP) method for histochemical techniques. The strong noncovalent attraction between biotin and avidin or streptavidin is exploited in many histochemical, immunohistochemical, and in situ hybridization... 

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.

To address this problem, we have developed a new technology based on B-cell targeting [5-9], The approach features three critical steps antigen-based pre-selection of B cells formation of B cell and myeloma cell complexes by exploiting the specificity and strength of the interaction between biotin and avidin and selective fusion of B cell-myeloma cell complexes with electrical pulses. This confers at least a 5-40-fold increase in efficiency over that obtained with the PEG-mediated method [8], Recently, we have successfully confirmed the efficacy of all three critical steps of B-cell targeting on the basis of immunofluorescence analysis [9],... 

The interaction between biotin and avidin/SA is also used to immobilize DNA. Usually, avidin/SA is physically immobilized on the substrate, where the specific binding sites of avidin/SA allow the immobilization of biotinylated ssDNA as the probe [21-27]. It is of great advantage that a chemically stable DNA chip can be readily prepared by this technique. 

Ce,Tb NPs to avidin-coated gold NPs based on the high affinity of biotin and avidin. 

Normal (un-enhanced) Raman spectra of biotin and avidin were obtained using the following procedure. Aqueous solutions at working concentrations of the various chemicals used throughout these experiments were deposited onto aluminum-coated glass microscope slides. Once these drops had dried sufficiently to produce the characteristic coffee ring shaped deposition, normal Raman spectra were acquired for comparison with the SERS spectra. 

Because of high affinity, the first ligand-receptor pair chosen by researchers for testing with AFM was biotin and streptavidin which was soon followed by biotin and avidin. Deduced from a broad distribution of AFM forces, it was concluded that the strength of a biotin-streptavidin... 

Fig. 11. Selection scheme for generation of an RNA ligase [86] [87]. Biotin and avidin are represented by B and Av, respectively.

An interaction between biotin and avidin is one of the strongest biomolecular interacting systems. Therefore an introduction of biotin derivatives to proteins facilitates their efficient purification/characterization. 

The reactivity of biotin with several reagents can be exploited in some chemical assays like its reaction with diazo derivatives, or the reaction of the ureido ring with p-dimethylaminocinnamaldehyde in an acidic medium, but the sensitivity of these assays is relatively poor. Several methods described for biotin assay involve a competitive complex formation between biotin and avidin bound with a chromophore/ fluorophore probe. In these assays, biotin, which has a higher affinity for avidin, quantitatively displaces the probe from the complex. 

Another application of QTL probe is to monitor enzymatic activity. For example, avidin was bound to PPE-coated microspheres to monitor protease activity using a similar fluorescence tum-on method." In this assay, a peptide was modified with biotin at one end and a fluorescence quencher at the other end. The specific binding between biotin and avidin was used to bring the quencher close to the microspheres in order to quench the fluorescence of the PPL. However, in the presence of protease, the peptide was hydrolyzed, cleaving the tether, and turning on the fluorescence of the PPE. 

Vreeke, M., Rocca, P., and Heller, A., 1995. Direct electrical detection of dissolved biotinylated horseradish-peroxidase, biotin, and avidin. Analytical Chemistry. 67 303-306. 

When two molecules need to be non-covalently brought together in the creation of a device, one can exploit the natural interaction between biotin and avidin. Biotin is a cofactor that binds to the protein receptor avidin (or strep-avidin), and the binding constant has been measured to be near 10 - M h This is one of the largest affinities associated with any molecular recognition event, and can be considered irreversible. Avidin is a tetrameric protein that binds four biotins independently. The fact that the protein binds four biotins and has such a large affinity for each, makes this system a powerful tool for assembly processes. 

A few methods based on fluorescence have been described for biotin and avidin determinations. A first one is based on the quenching of the avidin tryptophan fluorescence by biotin upon binding (71). A second one involves the increase of the fluorescence of avidin labeled with fluorescein isothiocyanate upon binding of biotin (72). The latter technique has been applied to HPLC postcolumn detection of biotin (see below). The sensitivities are, respectively, 20 and 0.5 ng. Another method is based on the variation of the fluorescence polarization of a biotin-fluorescein derivative upon interaction with avidin (73). Minimal detectable concentrations reported were 5 ng for avidin and 0.1 ng for biotin (73). Mock et al. reported another technique relying on the displacement by biotin of the fluorescent probe 2-anilinonaphthalene-6-sulfonic acid (2,6-ANS) (Fig. 10) when bound to avidin (74). The advantage of this method is obviously the large increase of fluorescence of 2,6-ANS when bound to avidin as compared to the unbound form in water solution. The detection limit was around 1 ng. This technique has also been applied to postcolumn detection of biotin (see below). 

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