Traptavidin Protein

Traptavidin is the S52G, R53D mutant of streptavidin, the high affinity biotin binding protein. Useful in various imaging, protein purification, and nano-assembly applications.


  • 10-fold lower off-rate from biotin and biotin conjugates compared to streptavidin
  • Increased thermal stability and mechanical stability of biotin binding compared to streptavidin
  • Shows low non-specific binding to cells and DNA

Streptavidin binds biotin-conjugates with exceptional stability, but dissociation does occur and can be limiting in imaging, DNA amplification, and nanotechnology. This Traptavidin protein overcomes these limitations with a ~10-fold slower biotin off-rate, increased mechanical strength, and improved thermostability compared to streptavidin.

From the laboratory of Mark Howarth, PhD, University of Oxford.

Catalog Number Product Size AVAILABILITY Price Qty
Traptavidin, 0.5mg
0.5mg (2.11mg/mL) Unavailable
Regular Price:$200.00
Contact us for details.

Product Type: Protein
Accession ID: ADT80793.1
Source: Recombinant, expressed in E. coli
Molecular Weight: 13.2 kDa (without boiling, traptavidin will run on SDS-PAGE as a tetramer and remain bound to biotin)
Fusion Tag(s): None
Purity: >98% by SDS PAGE (Purified from inclusion body refolding with selective ammonium sulfate precipitation and then iminobiotin-agarose affinity chromatography.)
Buffer: Phosphate buffered saline (PBS) pH 7.4; The protein is highly stable and should be compatible with a wide range of salts, ionic strengths and pH values (certainly 5-9), as well as DMF or DMSO up to 10%.
Concentration: 2.11 mg/mL (40 uM tetramer) in PBS.
Comments: 10-fold lower off-rate from biotin and biotin conjugates compared to streptavidin. Increased thermal stability and mechanical stability of biotin binding.
Storage: -80°C, stable for 1-2 weeks when kept at 4°C (avoid multiple freeze-thaw cycles)
Shipped: Dry ice


Purity, Binding, and Thermostability of Traptavidin Protein

Traptavidin Figrure

(A) SDS-PAGE analysis of purified Traptavidin protein after boiling. (B) Off-rate for biotin-4-fluorescein at 37°C (mean ± 1 s.d.). (C) Thermostability of biotinylated DNA binding: Streptavidin/Traptavidin-bound DNA heated at indicated temp. for 3 min, in presence of competing free biotin, before agarose gel electrophoresis.

From the laboratory of Mark Howarth, PhD, University of Oxford.

Traptavidin has a reduced on-rate compared to streptavidin, depending on the nature of the biotin conjugate; binding should still be rapid when working with high concentrations of biotinylated target, but for binding sub-micromolar concentrations of biotinylated target then longer should be allowed for binding than would be required for streptavidin.

Theoretical pI for traptavidin: 5.1 (6.1 for streptavidin)

Extinction coefficient (from ProtParam) at 280 nm: 41,940 M-1cm-1

  1. Chivers CE, Crozat E, Chu C, Moy VT, Sherratt DJ, Howarth M. A streptavidin variant with slower biotin dissociation and increased mechanostability. Nature Methods 2010 May;7(5):391-93.
  2. Chivers CE, Koner AL, Lowe ED, Howarth M. How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer. Biochemical Journal 2011 Apr 1;435(1):55-63.
  3. Fu H, Jiang Y, Yang D, Scheiflinger F, Wong WP, Springer TA. Flow-induced elongation of von Willebrand factor precedes tension-dependent activation. Nat Commun. 2017 Aug 23;8(1):324. View Article
  4. Qing Y, Ionescu SA, Pulcu GS, Bayley H. Directional control of a processive molecular hopper. Science. 2018 Aug 31;361(6405):908-912. View Article
  5. Talreja D, Cashman SM, Dasari B, Kumar B, Kumar-Singh R. G-quartet oligonucleotide mediated delivery of functional X-linked inhibitor of apoptosis protein into retinal cells following intravitreal injection. Exp Eye Res. 2018 Oct;175:20-31. View Article

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