Streptomyces avidinii Streptavidin (aa 25 - 183) [His], recombinant protein from E. coli
Streptomyces avidinii Streptavidin (CAA27265, P22629, 25 a.a. - 183 a.a.) partial recombinant protein with His tag expressed inEscherichia coli .
In 20 mM Tris, pH 7.5
2-8°C short term, -20°C long term
The streptavidin fluorochrome conjugates are commonly used in indirect staining protocols to detect biotinylated primary antibodies in flow cytometry. Streptavidin binds to biotin with high affinity.
Streptavidin is not the only protein capable of binding to biotin with high affinity. Avidin is the other most notable biotin-binding protein. Originally isolated from egg white, avidin only has 30% sequence identity to streptavidin, but almost identical secondary, tertiary and quaternary structure. It has a higher affinity for biotin but in contrast to streptavidin, it is glycosylated, positively charged, has pseudo-catalytic activity (it can enhance the alkaline hydrolysis of an ester linkage between biotin and a nitrophenyl group) and has a higher tendency for aggregation. Also, streptavidin is the better biotin-conjugate binder; avidin has a lower binding affinity than streptavidin when biotin is conjugated to another molecule, despite avidin having the higher affinity for free, unconjugated biotin.
Streptavidin; S. avidinii Streptavidin; Streptomyces avidinii Streptavidin