Streptavidin (HRP)

Streptavidin is a 22- 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. Peroxidase used for conjugation is 44 kDa glycoprotein isolated from horseradish roots. The Rz (Reinhetszahl), absorbance ratio of A43/A275 is ~3.. One mg of Streptavidin is conjugated with peroxidase, in equimolar ratio. Unconjugated Streptavidin is removed.