Active Biotinylated Proteins

Avi-tag and chemically labeled biotinylated proteins

Biotinylated proteins are powerful tools used in a wide variety of assay formats, including immunoprecipitation, flow cytometry, immunoassays, biopanning, and surface plasmon resonance. Historically, individual labs have made their own biotinylated proteins in small batches. However, often times researchers encounter protein-specific technical challenges and high variability leading to inconsistent results.

R&D Systems now offers a wide assortment of biotinylated proteins allowing researchers to take the guesswork out of protein biotinylation. In addition to amine-labeled biotinylated proteins, we have a growing list of Avi-tag biotinylated proteins. Each biotinylated protein is held to the same industry-leading quality standards as their unlabeled counterpart while also limiting batch-to-batch variability. Also, the R&D Systems Custom Protein Development Team can work with you to create a customized protein solution to meet your specific research needs.

What is Avi-tag?

Avi-tag Biotinylated Proteins are proteins that feature biotinylation at a single site contained within the Avi-tag, a unique 15 amino acid peptide. The DNA sequence coding for the Avi-tag is inserted during cloning and contained in the final expression vector construct. Biotinylation of the Avi-tag is enzymatically added by the E. coli biotin ligase BirA.

Advantages of Avi-Tag Biotinylated Recombinant Proteins

  • 1. Uniform labeling. Biotinylation only occurs on the single lysine residue in the Avi-tag.
  • 2. Uniform orientation of protein. When bound to a streptavidin-coated surface, the avitagged protein orientation will be uniform due to the precise control over biotinylation.
  • 3. Equivalent bioactivity. Because biotinylation is restricted to the Avitag, the rest of the protein is unchanged so there is no interference in the protein’s bioactivity.

Figure showing benefit of Avi-tag protein orientation bound to a streptavidin-coated surface.

Avi-tag biotinylated recombinant protein binding to streptavidin-coated surface

Avi-Tag Proteins

Protein Species Source Tag Catalog # Activity
B7-1/DC80 Human CHO His, Avi-tag AVI9050 BindsCTLA-4
BCMA/TNFRSF17 Human HEK293 Fc, Avi-tag AVI193 BindsAPRIL/TNFSF13
CD47 Human CHO Fc, Avi-tag AVI4670 BindsSIRP alpha/CD172a
CD155/PVR Human HEK293 Fc, Avi-tag AVI9174 BindsCD96v2
CTLA-4 Human HEK293 Fc, Avi-tag AVI7268 BindsB7-1/CD80
ErbB2/Her2 Human HEK293 Fc, Avi-tag AVI1129 BindsTrastuzumab
Fc gamma RIII Human HEK293 His, Avi-tag AVI8894 Binds human IgG
LAIR2 Human HEK293 His, Avi-tag AVI2665 Binds bovine Collagen I
PD-1 Human HEK293 His, Avi-tag AVI8986 BindsPD-L1/B7-H1
PD-L1/B7-H1 Human HEK293 His, Avi-tag AVI9049 BindsPD-1
Human CHO Fc, Avi-tag AVI156 BindsPD-1
uPAR Human HEK293 His, Avi-tag AVI807 BindsuPA/Urokinase
VEGF 165 Human HEK293 Fc, Avi-tag AVI7126 BindsVEGFR1/Flt-1
VISTA/B7-H5/PD-1H Human HEK293 Fc, Avi-tag AVI7126 BindsVSIG3

Amine-labeled and Sugar-labeled Biotinylated Proteins

We use R&D Systems best-in-class, highest quality recombinant proteins for biotinylation in an optimized process ensuring high labeling efficiency and lot-to-lot consistency. Proteins typically average multiple biotins per molecule making them an excellent choice when detection level is critical.

Amine-labeled and Sugar-labeled Biotinylated Proteins

Angiopoietin-1 Angiopoietin-2 Angiopoietin-like 4 Angiopoietin-like 4, N-term Angiopoietin-like 7 B7-H3
B7-H4 B7-H6 B7-H7 BMP-6 BMP-7 BTN1A1
BTN2A2 BTN3A2 BTNL8 CD155/PVR CD277/BTN3A1 Dkk-1
Frizzled-8 ICOS IL-17A IL-17A/F Heterodimer IL-2 IL-6
LAG-3 LIF Mouse Angiopoietin-like 3, N-term Mouse Wnt-3a PD-1 PD-L1
PD-L2 PDGF-BB R-Spondin-1 SIRP alpha TNF-alpha VEGF
Viral B18R (Type I IFN
decoy receptor)
Viral B8R (IFN-gamma
decoy receptor)
VISTA VSIG4 SIG8 Wnt-5a

Biotinylated protein features:

Equivalent Bioactivity

Consistent bioactivity between biotinylated and non-biotinylated proteins

Biotinylated Recombinant Human PD-L1/B7-H1 Fc Avi-tag protein
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Biotinylated recombinant human VEGF protein
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Biotinylated recombinant TNF-alpha protein
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Both Biotinylated Recombinant Human PD-L1/B7-H1 Fc Avi-tag and unlabeled Recombinant Human PD-L1/B7-H1 inhibit anti-CD3 antibody-induced IL-2 secretion in human T lymphocytes. The similarity in activity highlights that the biotinylated Avi-tag protein is fully functional. Both Biotinylated Recombinant Human VEGF 165 (Catalog # BT293) and unlabeled Recombinant Human VEGF 165 (Catalog # 293-VE) stimulate HUVEC human umbilical vein endothelial cell proliferation. The ED50 for this effect is 1-6 ng/mL. The similarity in activity highlights that the biotinylated protein is fully functional. Both Biotinylated Recombinant Human TNF-alpha (Catalog # BT210) and unlabeled Recombinant Human TNF-alpha (Catalog # 210-TA) promotes cytotoxicity in L‑929 mouse fibroblast cells in the presence of the metabolic inhibitor actinomycin D. The ED50 for this effect is 25-100 pg/mL. The similarity in activity highlights that the biotinylated protein is fully functional.

Binding activity

Biotinylated recombinant PD-1 His-tag Avi-tag protein
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Recombinant APRIL/TNFSF13 protein
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Recombinant VSIG3 protein
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When 500 ng/mL of Biotinylated Recombinant Human PD-1 His-tag Avi-tag protein is immobilized onto Streptavidin coated plate (Catalog # CP004), it binds to Recombinant Human PD-L1/B7-H1 Fc Chimera (Catalog # 156-B7) with an ED50 of 1.2-7.2 ng/mL. When Recombinant Human APRIL/TNFSF13 (Catalog # 5860-AP) is immobilized at 0.1 µg/mL, Recombinant Human BCMA/TNFRSF17 Fc Chimera Avi-tag (Catalog # AVI193) binds with an ED50 of 0.3-1.8 ng/mL. When Recombinant Human VSIG3 Fc Chimera (Catalog # 9229-VS) is coated at 5 μg/mL, Biotinylated Recombinant Human VISTA/B7-H5/PD-1H Fc Chimera Avi-tag (Catalog # AVI7126) binds with an ED50 of 0.5-3 μg/mL.

Lot-to-lot consistency

Biotinylated recombinant PD-L1/B7-H1 protein
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Three independent lots of B7-H1/PD-L1 have near identical bioactivity. When Recombinant Human PD-1 (Catalog #1086-PD) is coated at1 μg/mL, Biotinylated Recombinant Human PD-L1/B7-H1 Avi-tag (Catalog # AVI156) binds with an ED50 of 8-48 ng/mL.

Surface Plasmon Resonance (SPR)

BCD155/PVR-Fc Avi-tag protein
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Immobilized CD155/PVR-Fc Avi-tag (Catalog # AVI9174) bound to streptavidin CM5 chip binds to TIGIT-Fc (Catalog # 7898-TGB) with an affinity constant of 25.4 nM. Experiment performed on Biacore T200, GE Healthcare.

Other biotinylated recombinant protein resources:

All proteins from R&D Systems