Shop All Streptavidin & Conjugates

Streptavidin, horseradish peroxidase conjugate (Invitrogen™)

The streptavidin, horseradish peroxidase (HRP) conjugate can be used to detect biotin in a signal amplification scheme in conjunction with chromogenic substrates or fluorogenic HRP substrates, such as the tyramide signal amplification (TSA) technology.

Streptavidin Protein, AP (Invitrogen™)

Streptavidin for Western Blot, ELISA

eBioscience™ Streptavidin FITC Conjugate (Invitrogen™)

The streptavidin fluorochrome conjugates are commonly used in indirect staining protocols to detect biotinylated primary antibodies in flow cytometry. Streptavidin binds to biotin with high affinity.

Laser
Blue Laser

Emit
520 nm

Excite
488 nm

Reported Application
Flow Cytometric Analysis, Immunocytochemistry, Immunohistochemical Staining of Frozen Tissue Sections

Pierce™ Streptavidin Poly-HRP (Thermo Scientific™)

Thermo Scientific Pierce Streptavidin Poly-HRP conjugate is biotin-binding protein conjugated with polymers of horseradish peroxidase, enabling signal amplification and detection of biotinylated antibodies for IHC and other methods.

Features of Streptavidin Poly-HRP:

High sensitivity—detect low-abundant targets (low picogram-femtogram range) with high signal-to-noise ratios
Robust—consistent manufacturing and purification to eliminate low- and un-conjugated molecules for minimal background and high sensitivity
Flexible—compatible with chromogenic, fluorogenic and chemiluminescent substrates
Versatile—compatible with ELISA, Western blotting and immunohistochemistry (IHC)
Easy to use—can be directly substituted into immunoassays and other detection assays
Convenient—ready-to-use stabilized liquid format stored at 4°C
Cost effective—requires less conjugate per assay and standard HRP conjugates

Streptavidin Poly-HRP conjugate is designed to deliver the highest sensitivity and low background in immunoassays where sample volume is limited or when the target molecule is present at low levels. Streptavidin Poly-HRP is purified to remove unconjugated streptavidin molecules that reduce signal intensity by competing for binding sites with horseradish peroxidase (HRP)-conjugates molecules. In addition, the conjugate is devoid of HRP monomers that can cause background signal. The Pierce Streptavidin Poly-HRP is compatible with chromogenic, fluorogenic and chemiluminescent HRP substrates used in ELISA, Western blotting, immunohistochemistry (IHC) and nucleic acid hybridization assays.

Several forms of streptavidin-HRP conjugates are available that do not contain polymerized HRP (poly-HRP) and are suitable for most biotin detection assays. These and other commonly used HRP-conjugated antibodies and biotin-binding proteins are limited to one to three HRP molecules per protein in order to maintain functionality of the conjugate. This molar ratio of conjugation is effective in routine experiments but may lack the sensitivity required for detecting targets present in low picogram to femtogram amounts without the use of additional steps to amplify the signal.

When a higher degree of signal amplification is needed with standard HRP conjugates, methods such as peroxidase anti-peroxidase (PAP) systems or avidin-biotin complexes (ABC) can be used. However, these methods increase the cost of the assay and the number of steps that must be optimized. Pierce Streptavidin Poly-HRP circumvents such problems because it uses polymers of HRP molecules that are conjugated to streptavidin in a proprietary manufacturing process that increases the molar ratio of HRP on the conjugate while maintaining functionality. The increased molar ratio of HRP molecules to streptavidin results in more HRP molecules being available per binding event to react with the substrate. Therefore, Pierce Streptavidin Poly-HRP provides substantial signal amplification over other HRP-conjugates, eliminating the need for additional steps and saving time and expense.

As with all immunoassays, optimization is required to achieve the best signal-to-noise ratio. Switching to higher sensitivity substrates and conjugates can reveal more desired signal as well as background signal. If this occurs, follow standard primary and secondary dilution techniques or perform blocking buffer optimization.

Streptavidin, (R-PE) (Invitrogen™)

Class: RUO
Statement: For research use only. Not for use in diagnostic procedures.
Buffer: PBS
Preservative: 0.1% Sodium Azide

View a selection guide for all streptavidin RPE, APC, and tandem conjugates.

Streptavidin HRP (Invitrogen™)

Purified from Streptomyces avidinii and provided in a phosphate buffered saline solution. The streptavidin/avidin-biotin staining and detection strategy is used when increased assay sensitivity is desired for a wide variety of systems.

Format/Formulation: HRP Conjugate

Streptavidin, Allophycocyanin Conjugate, premium grade (Invitrogen™)

Streptavidin is a bacterially derived biotin-binding protein that reportedly exhibits less nonspecific binding than does avidin. Allophycocyanin is an intensely bright phycobiliprotein with a broad absorption profile that peaks at ~650 nm, and a fluorescence emission maximum of ~660 nm. Our streptavidin allophycocyanin conjugate *premium grade* is a further fractionation of our S-868 product, intended especially for applications that benefit from additional purity.

View a selection guide for all streptavidin RPE, APC, and tandem conjugates.

Qdot™ 585 Streptavidin Conjugate (Invitrogen™)

Qdot® 585 streptavidin conjugate comprises a biotin-binding protein (streptavidin) covalently attached to a fluorescent label (Qdot® nanocrystal). Streptavidin has a very high binding affinity for biotin, and a conjugate of streptavidin is commonly used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids, and other molecules (for example, a biotinylated primary antibody bound to a protein target can be detected with a fluorescently labeled streptavidin). Strategies similar to this are used in many detection protocols including western blots, flow cytometry, imaging and microscopy, and microplate assays, and are also used in purification workflows to achieve targeted fractionation. Qdot® nanocrystal conjugates are provided as 1 µM solutions.

Important Features of Qdot® Streptavidin Conjugates:
Streptavidin Qdot® 585 conjugate has emission maxima of ~585 nm
Approximately 5 to 10 streptavidins per Qdot® nanocrystal
Extremely photostable and bright fluorescence
Efficiently excited with single-line excitation sources
Narrow emission, large Stokes shift
Available in multiple colors
Ideal for western blots, flow cytometry, imaging and microscopy, microplate assays and more

Properties of Qdot® Nanocrystals
The Qdot® streptavidin conjugate is the size of a large macromolecule or protein (~15–20 nm) and represents the brightest class of streptavidin detection reagents. Qdot® streptavidin conjugates are made from a nanometer-scale crystal of a semiconductor material (CdSe), which is coated with an additional semiconductor shell (ZnS) to improve the optical properties of the material. The Qdot® 705 and Qdot® 800 streptavidin conjugates, which include CdSeTe, are made in a similar fashion. This core-shell material is further coated with a polymer shell that allows the materials to be conjugated to biological molecules and to retain their optical properties.

Other Fluorescent Conjugates of Streptavidin are Available
We offer several other Qdot® colors or try the Qdot® Streptavidin Sampler Kit, containing Qdot® streptavidin conjugates in six colors 525, 565, 585, 605, 655, and 705. In addition to nanocrystal conjugates, we offer a wide range of streptavidins conjugated to Alexa Fluor® dyes, Oregon Green® dye, enzyme conjugates, and traditional fluorophores like Texas Red® dye, fluorescein (FITC) and more.

Find Biotinylated Conjugates
We offer an extensive line of biotinylated conjugates for use in biotin-streptavidin detection strategies.
• Use the primary antibody search tool to find biotinylated primary antibodies
• Use the secondary antibody selector tool to find biotinylated secondary antibodies and biotinylated anti-dye and anti-hapten antibodies

Blocking Endogenous Biotin
Naturally occurring biotins can interfere with biotin-streptavidin detection schemes. For experiments involving fixed and permeabilized cells, try our Endogenous Biotin-Blocking Kit to minimize this interference.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Related Links:

Learn more about Avidin-Biotin Detection

To learn more about Qdot® Nanocrystals

Qdot™ 585 ITK™ Streptavidin Conjugate Kit (Invitrogen™)

The Qdot® 585 ITK™ Streptavidin Conjugate Kit provides the Qdot® streptavidin conjugate as 250 µL of a 2 µM solution. Unlike the Qdot® streptavidin conjugates, the Qdot® ITK™ streptavidin conjugates have the streptavidin covalently attached to the inner amphiphilic coating without a PEG linker. These Qdo® conjugates can be used for binding biotinylated probes. The kit also includes 30 mL of Qdot® incubation buffer.

Streptavidin, (FITC) (Invitrogen™)

Class: RUO
Statement: For research use only. Not for use in diagnostic procedures.
Buffer: PBS
Preservative: 0.1% Sodium Azide

View a selection guide for all Alexa Fluor® streptavidin and avidin conjugates.

Qdot™ 605 Streptavidin Conjugate (Invitrogen™)

Qdot® 605 streptavidin conjugate comprises a biotin-binding protein (streptavidin) covalently attached to a fluorescent label (Qdot® nanocrystal). Streptavidin has a very high binding affinity for biotin, and a conjugate of streptavidin is commonly used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids, and other molecules (for example, a biotinylated primary antibody bound to a protein target can be detected with a fluorescently labeled streptavidin). Strategies similar to this are used in many detection protocols including western blots, flow cytometry, imaging and microscopy, and microplate assays, and are also used in purification workflows to achieve targeted fractionation. Qdot® nanocrystal conjugates are provided as 1 µM solutions.

Important Features of Qdot® Streptavidin Conjugates:
Streptavidin Qdot® 605 conjugate has emission maxima of ~605 nm
Approximately 5 to 10 streptavidins per Qdot® nanocrystal
Extremely photostable and bright fluorescence
Efficiently excited with single-line excitation sources
Narrow emission, large Stokes shift
Available in multiple colors
Ideal for western blots, flow cytometry, imaging and microscopy, microplate assays and more

Properties of Qdot® Nanocrystals
The Qdot® streptavidin conjugate is the size of a large macromolecule or protein (~15–20 nm) and represents the brightest class of streptavidin detection reagents. Qdot® streptavidin conjugates are made from a nanometer-scale crystal of a semiconductor material (CdSe), which is coated with an additional semiconductor shell (ZnS) to improve the optical properties of the material. The Qdot® 705 and Qdot® 800 streptavidin conjugates, which include CdSeTe, are made in a similar fashion. This core-shell material is further coated with a polymer shell that allows the materials to be conjugated to biological molecules and to retain their optical properties.

Other Fluorescent Conjugates of Streptavidin are Available
We offer several other Qdot® colors or try the Qdot® Streptavidin Sampler Kit, containing Qdot® streptavidin conjugates in six colors 525, 565, 585, 605, 655, and 705. In addition to nanocrystal conjugates, we offer a wide range of streptavidins conjugated to Alexa Fluor® dyes, Oregon Green® dye, enzyme conjugates, and traditional fluorophores like Texas Red® dye, fluorescein (FITC) and more.

Find Biotinylated Conjugates
We offer an extensive line of biotinylated conjugates for use in biotin-streptavidin detection strategies.
• Use the primary antibody search tool to find biotinylated primary antibodies
• Use the secondary antibody selector tool to find biotinylated secondary antibodies and biotinylated anti-dye and anti-hapten antibodies

Blocking Endogenous Biotin
Naturally occurring biotins can interfere with biotin-streptavidin detection schemes. For experiments involving fixed and permeabilized cells, try our Endogenous Biotin-Blocking Kit to minimize this interference.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Related Links:

Learn more about Avidin-Biotin Detection

To learn more about Qdot® Nanocrystals

Streptavidin-Fluorescein Isothiocyanate (FITC) Conjugate (Invitrogen™)

Streptavidin-FITC conjugate is typically used in the immunodetection of biotinylated proteins. This conjugate is suitable for use in immunomicroscopy and fluorescence-activated cell sorting and analysis. The amount of conjugate provided is sufficient for 25 immunostaining reactions using 1 ml of working solution per reaction as appropriate.

Qdot™ 605 ITK™ Streptavidin Conjugate Kit (Invitrogen™)

The Qdot® 605 ITK™ Streptavidin Conjugate Kit provides the Qdot® streptavidin conjugate as 250 µL of a 2 µM solution. Unlike the Qdot® streptavidin conjugates, the Qdot® ITK™ streptavidin conjugates have the streptavidin covalently attached to the inner amphiphilic coating without a PEG linker. These Qdo® conjugates can be used for binding biotinylated probes. The kit also includes 30 mL of Qdot® incubation buffer.

Streptavidin Protein, DyLight 800 (Invitrogen™)

Streptavidin for Western Blot, IF, ICC, IHC, IP, ELISA

Streptavidin, Alexa Fluor™ 546 conjugate (Invitrogen™)

Alexa Fluor® 546 streptavidin comprises a biotin-binding protein (streptavidin) covalently attached to a fluorescent label (Alexa Fluor® dye). Streptavidin has a very high binding affinity for biotin, and a conjugate of streptavidin is commonly used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids, and other molecules (for example, a biotinylated primary antibody bound to a protein target can be detected with a fluorescently labeled streptavidin). Strategies similar to this are used in many detection protocols including western blots, flow cytometry, imaging and microscopy, and microplate assays. Alexa Fluor® dye streptavidin conjugates are supplied as 1 mg lyophilized product or in 0.5 mL volumes of a 2 mg/mL solution.

Important Features of Alexa Fluor® 546 Streptavidin Conjugates:
Alexa Fluor® 546 streptavidin conjugate has Ex/Em maxima of ~ (556/573)
Bright, photostable fluorescence
High solubility in aqueous solutions
Available in multiple colors
Ideal for western blots, flow cytometry, imaging and microscopy, microplate assays and more

Properties of Alexa Fluor® Dyes
Alexa Fluor® dyes are organic fluorescent dyes developed for better performance in imaging and other labeling protocols and exhibit improved photostability and brightness and improved solubility in aqueous solutions. Available in a broad range of colors, these dyes are a good choice for most imaging applications.

Blocking Endogenous Biotin
Naturally occurring biotins can interfere with biotin-streptavidin detection schemes. For experiments involving fixed and permeabilized cells, try our Endogenous Biotin-Blocking Kit to minimize this interference.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Related Links:

Learn more about Avidin-Biotin Detection

Learn more about Alexa Fluor® Dyes

Find out about other Labeled Streptavidin Conjugates

Read Avidin and Streptavidin Conjugates-Section 7.6 in the Molecular Probes Handbook