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Streptavidin, Avidin, Streptomyces avidinii
CAS Number:
MDL number:


lyophilized solid

Quality Level

specific activity

≥10 units/mg protein



storage condition

OK to freeze

shipped in


storage temp.


General description

A high affinity biotin binding protein (Kd approximately 10-15) that is stable over wide pH and temperature ranges. Each molecule of streptavidin binds 4 molecules of biotin. Streptavidin lacks the carbohydrate side chains present on avidin and has an isoelectric point nearer to neutrality (pI of 5.5-6.5 versus 10 for avidin). Consequently, streptavidin frequently exhibits lower levels of non-specific binding than avidin. The extinction coefficient of a 1% solution at 280 nm is 32.
A high-affinity biotin binding protein.


1, 10 mg in Plastic ampoule


Toxicity: Standard Handling (A)

Unit Definition

One unit is defined as the amount of streptavidin required to bind 1.0 µg of D-Biotin at pH 7.0.


Following reconstitution, aliquot and freeze (-20°C) for long term storage or refrigerate (4°C) for short-term storage. Aqueous stock solutions are stable for 6 months at 4°C and for up to 2 years at -20°C.
Reconstitute in H₂O or 1 mM NaHCO₃, pH 9.0 at twice the final concentration and then dilute with an equal volume of 2X buffer.

Other Notes

Eberle, J. and Seibl, R. 1992. J. Virol. Methods 40, 347.
Gudibande, S.R., et al. 1992. Mol. Cell. Probes. 6, 495.
Nesbitt, S.A. and Horton, M.A. 1992. Anal. Biochem. 206, 267.
Roth, J., et al. 1992. Histochemistry 98, 229.
Sano, T., et al. 1992. Science 258, 120.
Scouten, W.H. and Konecny, P. 1992. Anal. Biochem. 205, 313.
Srivastava, P., et al. 1992. Cytometry 13, 711.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

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Certificate of Quality

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