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Biotin and Streptavidin

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The biotin-streptavidin complex is one of the most popular tagging systems for the conjugation of biomolecules, such as proteins, lipids and nucleic acids, as well as that of synthetic molecules, such as fluorescent labels. It has found strong success in the area of sample preparation as a core part of many purification systems and plays a critical role in many detection systems for instruments such as microscopy and flow cytometry.

The widespread adoption of the biotin-streptavidin conjugation system is primarily due to two factors. The first is the relatively small size of the biotin and streptavidin molecules themselves, which allows for extensive binding to biologically active macromolecules, such as antibodies, without impedance to their functions (i.e. an antibody’s binding site). The second is the specificity with which biotin and streptavidin bind to each other, as well as the strength of the subsequent bond, which allows for powerful, stream-lined bioassay applications.

AAT Bioquest offers one of the most comprehensive catalogs of biotin and streptavidin products, their derivatives and their conjugates.  We also have a wide range of kits which have been designed to take advantage of the strengths of the biotin-streptavidin conjugation system and optimized to improve user convenience and workflow.

To learn more, please see the information below.

Biotin

Biotin, a 244 dalton vitamin, is present in trace amounts in all living cells. Besides having a strong affinity for streptavidin, biotin exhibits two characteristics that make it ideal for bioconjugate development. First, is biotin’s relatively small size. This minimizes any significant hindrance with the protein or antibody’s biological reactivity, and permits the labeling of multiple biotin tags to a single macromolecule for maximum detection by streptavidin and its conjugates.

Second, is the valeric acid side chain of the biotin molecule. This chain can be derivatized to incorporate various reactive groups used to biotinylate (i.e. label) proteins without altering its binding affinity for streptavidin. This feature is critical as it allows for the development of various biotinylated reagents. These include, amine-reactive biotin succinimidyl ester and thiol-reactive biotin maleimide, as well as, AAT Bioquest’s ReadiView™ reactive biotins and ReadiLink™ Protein Biotinylation Kit which enable researchers to chemically label proteins, nucleic acids and other molecules in order make custom assay probes.

Streptavidin Conjugates

Biotinylated proteins are routinely used in conjunction with streptavidin conjugates. Together, they form a sophisticated detection platform that is readily adaptable to a broad range of applications. A large factor that contributes to the versatility of the biotin-streptavidin system is the ability to conjugate streptavidin to a variety of reporter tags. For example, enzyme conjugates of streptavidin, such as HRP-streptavidin or AP-streptavidin, are commonly used in immunoblotting, ELISA and in situ hybridization imaging applications. While fluorescently labeled streptavidin , such as iFluor-streptavidin, are widely used in cell surface labeling, fluorescence activated cell sorting (FACs) and other fluroescence imaging applications.

Advantage of the Biotin-Streptavidin System

A key benefit of the biotin-streptavidin system is its ability to improve the detection sensitivity of any assay. This in large part is due to the tetrameric conformation of streptavidin, which enables streptavidin to bind four biotins per molecule with high affinity and selectivity. This multiplicity allows for amplification of weak signals, allowing for improved experimental results when testing for medium- to low- abundance targets in mammalian cells or tissues.

Table 1. Product ordering information for biotin, biotin derivatives, biotin conjugates and biotin kits.

Cat# Product Name Ex (nm) Em (nm) Size Price
3001 Biotin *CAS 58-85-5*     1 g $75
3002 Biotin, succinimidyl ester *CAS 35013-72-0*     100 mg $195
3003 Biotin ethylenediamine *CAS 216299-38-6*     10 mg $95
3004 Biotin cadaverine     25 mg $95
3005 Biotin C2 maleimide     25 mg $295
3006 Biotin-4-fluorescein *CAS 1032732-74-3* 492 518 5 mg $95
3007 Biotin hydrazide *CAS 66640-86-6*     25 mg $75
3009 Biotin-X NTA [Biotin-X nitrilotriacetic acid, potassium salt] *CAS 856661-92-2*     1 mg $95
3010 Biotin-X, succinimidyl ester *CAS 72040-63-2*     25 mg $75
3014 Biotin PEG2 amine *CAS 138529-46-1*     5 mg $95
3015 Biotin PEG2 maleimide *CAS 305372-39-8*     5 mg $95
3016 Biotin PEG2 succinimidyl ester     25 mg $95
3017 Fluorescein biotin 492 515 5 mg $95
3019 Biotin-PEG3-azide *CAS 945633-30-7*     5 mg $95
3020 Biotin Azide     5 mg $95
3021 Biotin Alkyne *CAS 1006592-45-5*     5 mg $95
3022 Biotin PEG4 succinimidyl ester     25 mg $95
3050 ReadiView™ biotin acid     25 mg $95
3053 ReadiView™ biotin amine     5 mg $195
3055 ReadiView™ biotin hydrazide     5 mg $195
3058 ReadiView™ biotin maleimide     5 mg $195
3059 ReadiView™ biotin succinimidyl ester     5 mg $95
5520 ReadiLink™ Protein Biotinylation Kit     2 Labelings $195
5521 ReadiLink™ Protein Biotinylation Kit *Powered by ReadiView™ Biotin Visionization Technology*     1 kit $195
5522 Amplite™ Colorimetric Biotin Quantitation Kit 500   200 Tests $195
16729 Biotinylated goat anti-mouse IgG (H+L)     1 mg $145
16794 Biotinylated goat anti-rabbit IgG (H+L)     1 mg $145
17016 Biotin-11-dUTP *1 mM in Tris Buffer (pH 7.5)* *CAS 86303-25-5*     25 nmoles $95
17017 Biotin-16-dUTP *1 mM in Tris Buffer (pH 7.5)* *CAS 136632-31-0*     25 nmoles $95
17018 Biotin-20-dUTP *1 mM in Tris Buffer (pH 7.5)*     25 nmoles $95
20605 Cal-520®-Biotin Conjugate 492 514 5x50 ug $295

 

Table 2. Product ordering information streptavidin conjugates.

Cat# Product Name Ex (nm) Em (nm) Size Price
16900 RPE-streptavidin conjugate 565 575 100 ug $95
16901 RPE-streptavidin conjugate 565 575 1 mg $295
16902 APC-streptavidin conjugate 651 662 100 ug $145
16905 PerCP-streptavidin conjugate 482 667 100 ug $195
16906 RPE-iFluor™ 647-streptavidin conjugate 565 674 100 ug $195
16907 RPE-iFluor™ 750-streptavidin conjugate 565 779 100 ug $195
16908 APC-iFluor™ 750-streptavidin conjugate 651 779 100 ug $195
16910 FITC-streptavidin conjugate 492 515 1 mg $145
16911 Texas Red®-streptavidin conjugate 582 602 1 mg $145
16912 Cy3®-streptavidin conjugate 555 565 1 mg $145
16913 Cy5®-streptavidin conjugate 649 665 1 mg $145
16914 Cy7®-streptavidin conjugate 749 776 1 mg $145
16920 HRP-streptavidin conjugate     1 mg $145
16921 AP-streptavidin conjugate [Streptavidin-alkaline phosphatase conjugate]     1 mg $145
16925 trFluor™ Eu-streptavidin conjugate 346 617 100 ug $295
16926 trFluor™ Tb-streptavidin conjugate 330 544 100 ug $295
16930 mFluor™ Violet 450-streptavidin conjugate 403 454 100 ug $95
16931 mFluor™ Violet 510-streptavidin conjugate 414 508 100 ug $95
16932 mFluor™ Violet 540-streptavidin conjugate 405 537 100 ug $95
16935 mFluor™ Blue 570-streptavidin conjugate 553 570 100 ug $95
16938 mFluor™ Green 620-streptavidin conjugate 523 617 100 ug $95
16942 mFluor™ Yellow 630-streptavidin conjugate 611 630 100 ug $95
16946 mFluor™ Red 700-streptavidin conjugate 657 700 100 ug $95
16948 mFluor™ Red 780-streptavidin conjugate 629 780 100 ug $95
16950 iFluor™ 350-streptavidin conjugate 345 442 200 ug $75
16952 iFluor™ 405-streptavidin conjugate 401 420 200 ug $75
16955 iFluor™ 488-streptavidin conjugate 491 514 200 ug $75
16956 iFluor™ 514-streptavidin conjugate 511 527 200 ug $75
16957 iFluor™ 532-streptavidin conjugate 536 560 200 ug $75
16958 iFluor™ 546-streptavidin conjugate 541 557 200 ug $75
16959 iFluor™ 555-streptavidin conjugate 552 567 200 ug $75
16960 iFluor™ 568-streptavidin conjugate 568 587 200 ug $75
16962 iFluor™ 594-streptavidin conjugate 592 614 200 ug $75
16965 iFluor™ 633-streptavidin conjugate 638 655 200 ug $75
16966 iFluor™ 647-streptavidin conjugate 654 674 200 ug $75
16968 iFluor™ 680-streptavidin conjugate 682 701 200 ug $75
16970 iFluor™ 700-streptavidin conjugate 693 713 200 ug $75
16973 iFluor™ 750-streptavidin conjugate 753 779 200 ug $75
16980 iFluor™ 350-streptavidin conjugate 345 442 1 mg $145
16982 iFluor™ 405-streptavidin conjugate 401 420 1 mg $145
16985 iFluor™ 488-streptavidin conjugate 491 514 1 mg $145
16986 iFluor™ 514-streptavidin conjugate 511 527 1 mg $145
16987 iFluor™ 532-streptavidin conjugate 536 560 1 mg $145
16989 iFluor™ 555-streptavidin conjugate 552 567 1 mg $145
16992 iFluor™ 594-streptavidin conjugate 592 614 1 mg $145
16995 iFluor™ 633-streptavidin conjugate 638 655 1 mg $145
16996 iFluor™ 647-streptavidin conjugate 654 674 1 mg $145
16997 iFluor™ 680-streptavidin conjugate 682 701 1 mg $145
16998 iFluor™ 700-streptavidin conjugate 693 713 1 mg $145
16999 iFluor™ 750-streptavidin conjugate 753 779 1 mg $145

 


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