nStreptavidin is biotin-binding protein that was originally isolated from Streptomyces avidinii. In contrast to avidin, streptavidin has no carbohydrate and has a mildly acidic pI of 5. Thermo Scientific Streptavidin products use a recombinant form of streptavidin having a mass of 53,000 daltons and a near-neutral pI. Streptavidin is a tetrameric protein, with each subunit binding one molecule of biotin with affinity similar to that of avidin. Guanidinium chloride will dissociate avidin and streptavidin into subunits, but streptavidin is more resistant to dissociation. Phycobiliprotein Concentration: 0.5mg/mL (determined by absorption = 73 at 650 nm for a 1% solution for only those APC molecules to which at least one molecule of active streptavidin is bound) Allophycocyanin Source: Spirulina platensis Working Dilution Range: 1:50-1:200 for most applications. Absorption Maxima: 650 nm Emission Maximum: 660 nm Restoration and Storage: Store freeze-dried product at 4°C until reconstitution. Restore with 0.5 ml distilled water. Centrifuge product if it is not completely clear after reconstitution. To judge clarity, draw product into a pasteur pipette. Store at 4°C. [Do not freeze]. After dilution, do not use for more than one day. Country of origin: USAnnorigin: US