Streptavidin (TxRd)

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: Streptavidin used is 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. Texas Red: A max. 596 nm; E max. 62 nm. Fluorochrome / protein Absorbance ratio: A596 nm/ A28 nm.