Shop All Avidin, Streptavidin & Biotin

Streptavidin, Alexa Fluor™ 514 conjugate (Invitrogen™)

Alexa Fluor® 514 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® 514 Streptavidin Conjugates:
Alexa Fluor® 514 streptavidin conjugate has Ex/Em maxima of ~ (518/540)
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

eBioscience™ Streptavidin PE 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, Green Laser, Yellow-Green Laser

Emit
578 nm

Excite
488 - 561 nm

Reported Application
Flow Cytometric Analysis

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.

Qdot™ 705 ITK™ Streptavidin Conjugate Kit (Invitrogen™)

The Qdot® 705 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™)

Reactivity: FITC-SA will react with biotin.

Streptavidin, Alexa Fluor™ 488 Conjugate (Invitrogen™)

Alexa Fluor® 488 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® 488 Streptavidin Conjugates:
Alexa Fluor® 488 streptavidin conjugate has Ex/Em maxima of ~ (495/519)
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

NeutrAvidin Protein, DyLight 550 (Invitrogen™)

NeutrAvidin for IF

Streptavidin - Cy3 (Invitrogen™)

Reactivity: CY3-SA reacts with biotin.

eBioscience™ Streptavidin eFluor™ 710 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
Red Laser

Emit
710 nm

Excite
633 - 647 nm

Reported Application
Flow Cytometric Analysis

NeutrAvidin Protein (Thermo Scientific™)

Thermo Scientific™ NeutrAvidin Protein is a specially-prepared form of avidin that decreases background in biotin-binding.

Features include:
Near-neutral isoelectric point—pI = 6.3, more neutral than native avidin
Nearly devoid of glycosylation—decreased possibility of lectin binding compared to native avidin
No RYD recognition sequence—no known off-target binding domains like streptavidin
Affordable—significantly less expensive than streptavidin

NeutrAvidin Protein is deglycosylated native avidin from egg whites. Removal of the excess carbohydrate by an exclusive process yields a protein with a more neutral isoelectric point and less nonspecific binding properties. Purified NeutrAvidin Protein provides exceptional performance in western blot, ELISA, and IHC applications that require biotin-binding probes. Assay specificity, sensitivity, and signal-to-noise ratios with NeutrAvidin Protein are generally equivalent or better than with the significantly more expensive streptavidin.

Avidin is a glycoprotein found in the egg white and tissues of birds, reptiles, and amphibia. The biotin-binding protein contains four identical subunits having a combined mass of 67,000-68,000 daltons. Removing the glycosylation from avidin yields NeutrAvidin Protein with a mass of 60,000 daltons. Carbohydrate-based lectin binding is reduced to undetectable levels, yet biotin-binding affinity is retained. NeutrAvidin Protein offers the advantages of a neutral pI to minimize nonspecific adsorption, along with lysine residues that remain available for derivatization or other customized conjugation. NeutrAvidin Protein yields the lowest nonspecific binding among the known biotin-binding proteins. The specific activity for biotin binding is approximately 14 µg/mg of protein, which is near the theoretical maximum activity.

Related products
NeutrAvidin™ Protein, Horseradish Peroxidase Conjugated
NeutrAvidin™ Protein, Alkaline Phosphatase Conjugated
NeutrAvidin™ Protein, Fluorescein Conjugated
NeutrAvidin™ Protein, Maleimide-Activated

Streptavidin, Alexa Fluor™ 610—R-Phycoerythrin Conjugate (Alexa Fluor™ 610—R-Phycoerythrin Streptavidin) (Invitrogen™)

The streptavidin, Alexa Fluor™ 610-R-phycoerythrin streptavidin tandem conjugate has excitation and emission maxima at ~496,565/627 and is widely used to detect biotinylated probes by flow cytometry. Not only are the Alexa Fluor™ 610 conjugates of R-PE are more fluorescent than the commercially available Texas Red™ conjugates of R-PE, the fluorescent emission of Alexa Fluor™ 610-R-PE tandem conjugates is shifted to somewhat longer wavelengths than is the emission of Texas Red™-R-PE conjjgates, resulting in better separation from the emission of R-PE.

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

Streptavidin HRP (ELISA GD) (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 (ELISA grade)

Streptavidin, Alexa Fluor™ 555 Conjugate (Invitrogen™)

Alexa Fluor® 555 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® 555 Streptavidin Conjugates:
Alexa Fluor® 555 streptavidin conjugate has Ex/Em maxima of ~ (555/565)
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

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.

Related Links:
Learn more about Avidin-Biotin Detection
To learn more about Qdot® Nanocrystals

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

eBioscience™ Streptavidin eFluor™ 570 Conjugate (Invitrogen™)

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

Emit
570 nm

Excite
555 nm

Reported Application
Immunohistochemical Staining of Formalin-Fixed Paraffin Embedded Tissue Sections, Immunohistochemical Staining of Frozen Tissue Sections, Immunocytochemistry

Streptavidin Protein, AP (Invitrogen™)

Streptavidin for Western Blot, ELISA

Streptavidin Protein, DyLight 800 (Invitrogen™)

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

NeutrAvidin Protein, DyLight 650 (Invitrogen™)

NeutrAvidin for IF

Avidin, NeutrAvidin™, Oregon Green™ 488 conjugate (Invitrogen™)

Our Oregon Green® 488 conjugate of NeutrAvidin® biotin-binding protein - a form of avidin that has been processed to remove carbohydrate and to lower its isoelectric point - can substantially decrease background due to nonspecific binding. The method used to deglycosylate the avidin retains its specific binding. This bright, green-fluorescent reagent (absorption/emission maxima ~496/524 nm) is ideal for detecting biotinylated targets in fluorescence microscopy and flow cytometry applications.

Qdot™ 800 Streptavidin Conjugate (Invitrogen™)

Qdot® 800 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® 800 conjugate has emission maxima of ~800 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.

Related Links:
Learn more about Avidin-Biotin Detection
To learn more about Qdot® Nanocrystals

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

Streptavidin-CY3 (ZyMax Grade) (Invitrogen™)

Applications: Immunohistochemistry, Western blotting, ELISA, ISH

ZyMAX™ reagents offer enhanced assay sensitivity, higher titer, and greater flexibility in assay design than standard grade reagents.

eBioscience™ Streptavidin eFluor™ 450 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
Violet Laser

Emit
445 nm

Excite
405 nm

Reported Application
Flow Cytometric Analysis

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 - Cy5 (Invitrogen™)

Reactivity: CY5-SA reacts with biotin.

Avidin, NeutrAvidin™, Alexa Fluor™ 350 conjugate (Invitrogen™)

Our Alexa Fluor 350 conjugate of NeutrAvidin biotin-binding protein – a form of avidin that has been processed to remove carbohydrate and to lower its isoelectric point – can substantially decrease background due to nonspecific binding. The method used to deglycosylate the avidin retains its specific binding. This bright, blue-fluorescent reagent (absorption/emission maxima ~346/442 nm) is ideal for detecting biotinylated targets in fluorescence microscopy and flow cytometry applications.

Qdot™ 545 ITK™ Streptavidin Conjugate Kit (Invitrogen™)

The Qdot® 545 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, Alexa Fluor™ 647—R-Phycoerythrin Conjugate (Alexa Fluor™ 647—R-Phycoerythrin Streptavidin) (Invitrogen™)

The streptavidin, Alexa Fluor™ 647-R-phycoerythrin streptavidin tandem conjugate has excitation and emission maxima at ~496,565/667 and is widely used to detect biotinylated probes by flow cytometry in multicolor applications using a single excitation wavelength, 488 nm. The Alexa Fluor™ 647 conjugates of R-PE have emission spectra almost identical to those of Cy5-R-PE conjugates but tend to have more intesne long-wavelength emission and to require less compensation in the R-PE channel.

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

Streptavidin, Alexa Fluor™ 594 Conjugate (Invitrogen™)

Alexa Fluor® 594 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® 594 Streptavidin Conjugates:
Alexa Fluor® 594 streptavidin conjugate has Ex/Em maxima of ~ (590/617)
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

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

Streptavidin, Allophycocyanin, crosslinked, conjugate (Invitrogen™)

Streptavidin is a bacterially derived biotin-binding protein that reportedly exhibits less nonspecific binding than 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.

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

Avidin, NeutrAvidin™, Rhodamine Red™-X conjugate (Invitrogen™)

Our Rhodamine Red™-X conjugate of NeutrAvidin® biotin-binding protein - a form of avidin that has been processed to remove carbohydrate and to lower its isoelectric point - can substantially decrease background due to nonspecific binding. The method used to deglycosylate the avidin retains its specific binding. This bright, red-fluorescent reagent (absorption/emission maxima ~570/590 nm) is ideal for detecting biotinylated targets in fluorescence microscopy applications.

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.

Streptavidin Protein, DyLight 405 (Invitrogen™)

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

CaptAvidin™ Agarose (Sedimented Bead Suspension) (Invitrogen™)

CaptAvidin™ biotin-binding protein conjugated to agarose is designed for use in affinity chromatography. CaptAvidin™ biotin-binding protein contains a nitrated tyrosine in its biotin-binding site. This chemical modification permits dissociation of the avidin-biotin complex under milder conditions than the traditional avidin-biotin complex. At pH 4.0, CaptAvidin™ biotin-binding protein binds biotin tightly with a Ka of ~109M-1. This association can then be reversed at pH 10, allowing complete dissociation of the avidin-biotin complex. This is in contrast to the harsh conditions (8 M guanidine hydrochloride, pH 1.5) needed to dissociate the avidin-biotin complex.

Avidin, NeutrAvidin™ Biotin-binding Protein (Invitrogen™)

Our NeutrAvidin® biotin-binding protein- a form of avidin that has been processed to remove carbohydrate and to lower its isoelectric point - can substantially decrease background due to nonspecific binding. The method used to deglycosylate the avidin retains its specific binding.

Streptavidin Protein (Thermo Scientific™)

Thermo Scientific™ Pierce™ Streptavidin is a purified unconjugated recombinant protein.

Features include:
Recombinant streptavidin—high-quality protein, 53 kDa, pI = 6.8–7.5
Pure protein—choose pure, unconjugated protein for biotin blocking and controls

Purified recombinant streptavidin enables detection of biotinylated antibodies and other probes in a variety of standard assay methods, including western blotting, ELISA, immunohistochemistry, and fluorescence imaging. Purified streptavidin is supplied lyophilized in phosphate-based buffer for immediate reconstitution with water.

Streptavidin is a biotin-binding protein originally isolated from Streptomyces avidinii. In contrast to avidin, streptavidin has no carbohydrate and has a mildly acidic pI of 5. Pierce™ streptavidin products use a recombinant form of streptavidin having a mass of 53,000 daltons and a near-neutral pI. Streptavidin is a tetrameric protein, with each subunit binding one molecule of biotin with affinity similar to that of avidin. Guanidinium chloride will dissociate avidin and streptavidin into subunits, but streptavidin is more resistant to dissociation.

Applications: ELISA (assay dependent), western blot (assay dependent)

Related products
Pierce™ Streptavidin, Horseradish Peroxidase Conjugated
Pierce™ Streptavidin, Alkaline Phosphatase Conjugated
Pierce™ Streptavidin, Maleimide-Activated
Pierce™ Streptavidin, Hydrazide-Activated

Streptavidin, (APC-Alexa Fluor™ 750) (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.

Avidin, NeutrAvidin™, FITC conjugate (Invitrogen™)

Searching for superior alternatives to fluorescein? Our Alexa Fluor Dye Series offers everything you're looking for and more.

Streptavidin Protein, DyLight 594 (Invitrogen™)

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

Pierce™ Avidin (Thermo Scientific™)

Thermo Scientific Pierce Avidin is a purified avidin protein from hen egg whites that effectively binds biotin, a tag that is frequently used to tag antibodies and other probes for immunodetection methods.

Features of Pierce Avidin:

Native avidin—glycoprotein from chicken egg whites, 67kDa, pI = 10
Soluble—glycosylation and isoelectric point renders avidin more soluble than streptavidin
Affordable—significantly less expensive than recombinant streptavidin
ABC staining—avidin is usually preferred over streptavidin for avidin-biotin complex (ABC) staining methods in immunohistochemistry (IHC)
Pure protein—choose pure, unconjugated avidin for use in ABC staining

Avidin is a glycoprotein found in the egg white and tissues of birds, reptiles and amphibia. This protein contains four identical subunits having a combined molecular mass of 67,000 to 68,000 daltons. Each subunit binds one molecule of biotin, and studies have shown that tryptophan and lysine are involved in the binding site for biotin. The sequencing of the subunit indicates it consists of 128 amino acids. Avidin has an isoelectric point of 10-10.5 and is very soluble in water and salt solutions. Avidin is stable over a wide range of pH values and temperatures. Extensive chemical modification has little effect on the activity of avidin, making it useful for detection and protein purification.

Related Products
Pierce™ Avidin, Horseradish Peroxidase Conjugated
Pierce™ Avidin, Fluorescein (FITC) Conjugated

Streptavidin-CY5 (ZyMax Grade) (Invitrogen™)

Applications: Western blotting, ELISA, Immunohistochemistry, ISH

ZyMAX™ reagents offer enhanced assay sensitivity, higher titer, and greater flexibility in assay design than standard grade reagents.

Streptavidin, (PE-Cy7) (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 Protein, Rhodamine (Invitrogen™)

Streptavidin for Western Blot, IHC, ELISA

eBioscience™ Streptavidin PerCP-eFluor™ 710 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
710 nm

Excite
488 nm

Reported Application
Flow Cytometric Analysis

eBioscience™ Streptavidin PerCP-Cyanine5.5 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
695 nm

Excite
488 nm

Reported Application
Flow Cytometric Analysis

Qdot™ 525 Streptavidin Conjugate (Invitrogen™)

Qdot® 525 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® 525 conjugate has emission maxima of ~525 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.

Related Links:
Learn more about Avidin-Biotin Detection
To learn more about Qdot® Nanocrystals

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

eBioscience™ Streptavidin APC-eFluor™ 780 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
Red Laser

Emit
780 nm

Excite
633 - 647 nm

Reported Application
Flow Cytometric Analysis

Streptavidin, R-Phycoerythrin Conjugate (SAPE) - premium grade - 1 mg/mL (Invitrogen™)

The R-phycoerythrin (R-PE) conjugate of streptavidin comprises a biotin-binding protein (streptavidin) covalently attached to a fluorescent label (R-phycoerythrin). 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). Streptavidin R-PE is very valuable in biotin-streptavidin detection protocols developed for flow cytometry, microplate assays, and microarrays. This R-PE streptavidin conjugate is a high-purity product (purity confirmed by HPLC) and is supplied as 1 mL of a 1 mg/mL solution.

Important Features of Streptavidin RPE:
Ex/Em maxima of ~ (496, 546, 565/578) nm
5 to 10 times brighter than organic dyes
Very high solubility in aqueous solutions
Free of all unconjugated streptavidin; and mostly free of unconjugated R-PE
Ideal for flow cytometry, microplate assays, and microarrays

Properties of R-phycoerythrin
R-PE has a quantum efficiency of 78%, making it an incredibly bright reagent, useful where high sensitivity is needed. Because of poor photostability, however, it is not recommended for fluorescence microscopy.

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

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 the practical applications for Streptavidin R-PE

Streptavidin, Alexa Fluor™ 568 conjugate (Invitrogen™)

Alexa Fluor® 568 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® 568 Streptavidin Conjugates:
Alexa Fluor® 568 streptavidin conjugate has Ex/Em maxima of ~ (578/603)
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

LanthaScreen™ Tb-Streptavidin, 1 mg/mL Kit

As part of the LanthaScreen® TR-FRET Toolbox of assay reagents, LanthaScreen® Tb-labeled streptavidin is a "generic" reagent that can be used to easily label biotinylated biomolecules with terbium for use in TR-FRET assays. Although the terbium chelate donor can be directly attached to a biomolecule such as a protein or peptide, the Tb-labeled streptavidin can be "indirectly" attached to a target molecule through a biotin-mediated association with Tb-labeled streptavidin.

Streptavidin, Alkaline Phosphatase Conjugate (Invitrogen™)

The streptavidin, alkaline phosphatase conjugate can be used to detect biotin in a signal amplification scheme in conjunction with chromogenic substrates or fluorogenic substrates.

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.

Streptavidin (Invitrogen™)

Streptavidin is a bacterially derived biotin-binding protein that reportedly exhibits less nonspecific binding than avidin.

Capacity: Binding activity of streptavidin is determined to be >11 units per mg protein. One unit of binding activity is defined as that amount of protein which binds 1 µg of biotin (Green, N.M., Biochem. J., 89:599,1963)

Form: Streptavidin is provided in lyophilized form in 10 mM phosphate buffered saline, pH 7.4. Reconstitute with 1 ml of distilled or deionized water.

Storage: Store at 4°C.

NeutrAvidin Protein, DyLight 488 (Invitrogen™)

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

Streptavidin Protein, DyLight 650 (Invitrogen™)

Streptavidin for IF

Avidin, NeutrAvidin™, PE conjugate (Invitrogen™)

Our R-phycoerythrin (R-PE) conjugate of NeutrAvidin® biotin-binding protein - a form of avidin that has been processed to remove carbohydrate and to lower its isoelectric point - can substantially decrease background due to nonspecific binding. The method used to deglycosylate the avidin retains its specific binding. This bright, fluorescent reagent is ideal for detecting biotinylated targets in flow cytometry applications.

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

eBioscience™ Streptavidin eFluor™ 615 Conjugate (Invitrogen™)

The streptavidin fluorochrome conjugates are commonly used in indirect staining protocols to detect biotinylated primary antibodies in immunohistochemistry and immunocytochemistry applications. Streptavidin binds to biotin with high affinity.

Emit
615 nm

Excite
595 nm

Reported Application
Immunocytochemistry, Immunohistochemical Staining of Frozen Tissue Sections, Immunohistochemical Staining of Formalin-Fixed Paraffin Embedded Tissue Sections

Streptavidin Protein, DyLight 680 (Invitrogen™)

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

Pierce™ High Sensitivity Streptavidin-HRP, Pre-Diluted (Thermo Scientific™)

Thermo Scientific Pierce High Sensitivity Streptavidin-HRP, 2 mL is an exclusive peroxidase-conjugated streptavidin biotin-binding protein that provides signal amplification like poly-HRP and exceptional storage stability.

Features of High Sensitivity Streptavidin-HRP, 2 mL:

High sensitivity—detect low levels of target without background; obtain high signal-to-noise ratios
Cost effective—use less conjugate in Western blotting and ELISA applications and still obtain excellent results
Flexible—compatible with typical chemiluminescent, fluorescent and colorimetric peroxidase substrates
Convenient—ready-to-use stabilized liquid format means there is no waiting for thawing and no need to aliquot

This specially-manufactured variety of HRP-conjugated streptavidin protein meets the demands of today's scientists for more sensitive detection in ELISA and Western blotting applications. The conjugate is suitable for use with chemiluminescent, chemifluorescent or colorimetric substrates. Each High Sensitivity HRP conjugate is packaged in an easy-to-use stabilized solution that enables convenient storage at 4°C for at least one year.

Our High Sensitivity HRP Conjugates outperform the competition on target detection, signal intensity and signal-to-noise ratios. Experiments indicate that the High Sensitivity Streptavidin-HRP can be diluted 8-to 10-fold more than traditional HRP conjugates and still produce similar results.

Related Products
Pierce™ High Sensitivity Streptavidin-HRP