Streptavidin (FITC)

Streptavidin is a 55 kDa (subunit MW 14 kDa) biotin-binding protein isolated from Streptomyces avidini. Streptavidin is superior to avidin, because it does not contain carbohydrate like avidin and has no net charge at neutral pH. Streptavidin~biotin system is routinely used in Immunohistochemistry (IHC). Extinction Coefficient 1% A28=32.. Purity: > 99% pure by HPLC; Eletrophoretically homogenous, single band. Protein content: > 95%; Activity 14.8 units/ mg, one unit bunds 1. microgram of d-biotin; Protease activity: .18 units/mg; Isoelectric point: 7. +/- determined by Isoelectric focusing. One mg of Streptavidin is conjugated with FITC, unconjugated Streptavidin is removed. This conjugate of streptavidin is recommended for use with Biotin~conjugated antibodies. Avidin~Biotin conjugated reagents are stable, sensitive and give less background. Fluorophore: Fluorescein isothiocyanate A max=492nm; E=52nm; Fluorophore/Protein: A492nm/A28nm=~1