Shop All Avidin, Streptavidin & Biotin

Streptavidin, Rhodamine Red™-X conjugate (Invitrogen™)

The streptavidin, Rhodamine-Red™-X conjugate has excitation and emission maxima ~570/590 and is widely used to detect biotinylated probes by fluorescence microscopy.

Avidin, NeutrAvidin™, Horseradish Peroxidase conjugate (Invitrogen™)

Our horseradish peroxidase (HRP) 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.

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™ 405 conjugate (Invitrogen™)

Our streptavidin, Alexa Fluor 405 conjugate is a bright, photostable probe with excitation/emission maxima of 402 and 421 nm. Streptavidin is a nonglycosylated biotin-binding protein that is isolated from bacteria and has a near-neutral isoelectric point. It is widely used to detect biotinylated probes, because it reportedly exhibits less nonspecific binding than does the glycosylated, biotin-binding protein, avidin.

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

Streptavidin Protein, DyLight 633 (Invitrogen™)

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

Avidin, HRP conjugate (Invitrogen™)

Reactivity: HRP-Avidin reacts with biotin.

Applications: Immunohistochemistry, ELISA

Streptavidin, Alexa Fluor™ 430 conjugate (Invitrogen™)

Our Alexa Fluor 430 streptavidin conjugate is a bright, green-fluorescent probe (absorption/emission maxima ~434/539 nm). Streptavidin, a nonglycosylated biotin-binding protein with a near-neutral isoelectric point, reportedly exhibits less nonspecific binding than avidin.

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

Streptavidin, Pacific Orange™ conjugate (Invitrogen™)

Pacific Orange™ streptavidin has absorption/emission maxima of ~400/551 nm. Streptavidin is a nonglycosylated biotin-binding protein that is isolated from bacteria and has a near-neutral isoelectric point. It is widely used to detect biotinylated probes, because it reportedly exhibits less nonspecific binding than does the glycosylated, biotin-binding protein, avidin.

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

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.

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

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.

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

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

Streptavidin Protein, AP (Invitrogen™)

Streptavidin for Western Blot, ELISA

Streptavidin, (APC) (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.