Streptavidin is a biotin binding protein present in the fermentation broth of the bacterium Streptomyces avidinii. Each molecule of streptavidin can bind four molecules of biotin with a high affinity constant (K_d~10 ^-15). Unlike native avidin, streptavidin is not glycosylated and has a near neutral isoelectric point (pI ~ 5-6) vs a pI of 10 for native avidin.

Streptavidin is lyophilized under slight alkaline conditions from deionized water. The final lyophilized protein contains approximately 10% NaCl.

The lyophilized streptavidin is stable for at least one year when stored desicated at –20°C. It is recommended to only reconstitute the amount required for use. However, any unused reconstituted streptavidin should be aliquoted in working volumes without diluting and stored at –20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

Next Day Ambient