• Product Name: Recombinant Strep-Tactin with Cysteine, r-STC
• Catalog Number: NRPA17S
• Packing Details：1 mg，10 mg，100 mg，500 mg
• Formulation: Lyophilized from 5mM PB(2.5mM Na2HPO4,2.5mM NaH2PO4, pH6.8)
• Mol. Wt.: Subunit 13.4 kDa; Tetramer 53.6 kDa
• Theory pI：8.12
• Theory Activity：18.2 U/mg protein (r-STc:Biotin = 1:4(mol:mol))
• Activity：≥15 U/mg protein（Green improved method）
• Purity: ≥95%（SDS-PAGE）
• Concentration determination: 280nm absorption method, molar absorption coefficient is 1.68×105(mol/L)-1·cm-1，c(g/L) = A280nm/3.13
• Endotoxin：≤5EU/mg
• Storage Condition: -20 oC
• Storage Duration: 3 years

Streptavidin is a streptavidin mutant, which can specifically bind streptavidin. The Strep II tag is a small 8 amino acid tag (wshpqfek). Since the tag is small, it is only about 1 kDa, which generally does not affect the structure and function of the fusion protein. It is commonly used in the detection and purification of fusion proteins.

Compared to streptavidin, streptavidin has a 10-fold higher affinity for streptavidin. It can bind and dissociate with streptavidin under mild conditions and can play a good role in separation and purification. In order to be able to bind to the medium, cysteine has been added to the C-terminal end of the amino acid sequence, which can be covalently linked to the medium through a sulfhydryl group.