膜杰作
Star Staining
分子别名（Synonym）
Streptavidin,SA
表达区间及表达系统（Source）
Streptavidin Protein-FITC (STN-NF113) is expressed from E. coli cells.
蛋白结构（Molecular Characterization）
The protein has a calculated MW of 13.8 kDa.
偶联（Conjugate）
FITC
Excitation source: 488 nm spectral line, argon-ion laser
Excitation Wavelength: 488 nm
Emission Wavelength: 535 nm
标记（Labeling）
The primary amines in the side chains of lysine residues and the N-terminus of the protein are conjugated with FITC using standard chemical labeling method. The residual FITC is removed by molecular sieve treatment during purification process.
蛋白标记度（Protein Ratio）
The FITC to protein molar ratio is 3-6.
应用说明（Application）
Flow Cytometry
内毒素（Endotoxin）
Less than 1.0 EU per μg by the LAL method.
纯度（Purity）
>90% as determined by SDS-PAGE.
制剂（Formulation）
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4 with trehalose as protectant.
Contact us for customized product form or formulation.
重构方法（Reconstitution）
Please see Certificate of Analysis for specific instructions.
For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.
存储（Storage）
For long term storage, the product should be stored at lyophilized state at -20°C or lower.
Please protect from light and avoid repeated freeze-thaw cycles.
This product is stable after storage at:
- -20°C to -70°C for 12 months in lyophilized state;
- -70°C for 3 months under sterile conditions after reconstitution.
活性（Bioactivity）-FACS
5e5 of Anti-CD19 CAR-293 cells were stained with 100 μL of 20 μg/mL Biotinylated Human CD19 (20-291) Protein, Fc,Avitag, premium grade (Cat. No. CD9-H82F6) and negative control protein respectively, washed and then followed with 1.25 μg/mL of Streptavidin Protein-FITC (Cat. No. STN-NF113) and analyzed with FACS. FITC signal was used to evaluate the binding activity (QC tested).
Protocol
背景（Background）
Streptavidin is a tetrameric protein purified from the bacterium Streptomyces avidinii, and exhibits high binding affinity for biotin. Able to bind one molecule of biotin with each subunit. Streptavidin (PI=6.0-7.5) has lower level of non-specific binding to various biological components at physiological pH than avidin (PI=7.4), resulting from its isoelectric point (PI).Streptavidin is useful in affinity chromatography, ELISA, immunohistochemistry and Western Blotting.
