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 (Kd~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.
DyLight® 550 conjugated antibodies absorb light maximally around 562 (± 4 nm) and fluoresce with a peak around 576 nm. They are brighter than TRITC conjugates, and they are equal in brightness to Cy3 and Alexa Fluor 555. All Dylight® 550 antibodies are recommended for maximum sensitivity in all immunofluorescence detection procedures within the orange-red portion of the visible spectrum.
DyLight® is a trademark of Thermo Fisher Scientific Inc. and its subsidiaries.
Streptavidin-DyLight® 550 is supplied in 0.01M phosphate buffered saline (PBS), 0.25M NaCl, pH 7.6, containing 15 mg/ml BSA and 0.05% sodium azide as a preservative.
Storage and Stability
The lyophilized streptavidin is stable when stored at 2-8°C. After reconstitution the streptavidin may be stored as an undiluted liquid at 2-8°C for six weeks. For extended storage as a liquid an equal volume of ACS grade or better glycerol should be added to the vial (bringing the final concentration of streptavidin to 50%) and stored at –20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. The reconstituted material may also be aliquoted and frozed at -70°C without the addition of glycerol.
Applications and Suggested Working Dilutions
0.5 - 2.0 µg/ml
Country of Origin
Products are for research use only. Not for use in diagnostic or therapeutic procedures.
359 Consort Drive | St. Louis, MO 63011 | (800) 538-1145 | (636) 527-5545 fax