Biotinylated Human CTLA-4, His,Avitag (CT4-H82E1) is expressed from human 293 cells (HEK293). It contains AA Ala 37 - Phe 162 (Accession # Q6GR94-1).
Predicted N-terminus: Ala 37
This protein carries a polyhistidine tag at the C-terminus, followed by an Avi tag.
The protein has a calculated MW of 17.2 kDa. The protein migrates as 22-30 kDa under reducing (R) condition (SDS-PAGE) due to glycosylation.
Biotinylation of this product is performed using Avitag™ technology. Briefly, the single lysine residue in the Avitag is enzymatically labeled with biotin.
The biotin to protein ratio is 0.5-1 as determined by the HABA assay.
Less than 1.0 EU per μg by the LAL method.
>95% as determined by SDS-PAGE.
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally trehalose is added as protectant before lyophilization.
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Please see Certificate of Analysis for specific instructions.
For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.
For long term storage, the product should be stored at lyophilized state at -20°C or lower.
Please avoid repeated freeze-thaw cycles.
No activity loss was observed after storage at:
- -20°C to -70°C for 12 months in lyophilized state;
- -70°C for 3 months under sterile conditions after reconstitution.
Biotinylated Human CTLA-4, His,Avitag on SDS-PAGE under reducing (R) condition. The gel was stained overnight with Coomassie Blue. The purity of the protein is greater than 95%.
Immobilized Human B7-1, Fc Tag (Cat. No. B71-H5259) at 2 μg/mL (100 μL/well) can bind Biotinylated Human CTLA-4, His,Avitag (Cat. No. CT4-H82E1) with a linear range of 0.8-25 ng/mL (QC tested).
CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4) is also known as CD152 (Cluster of differentiation 152), is a protein receptor that downregulates the immune system. CTLA4 is a member of the immunoglobulin superfamily, which is expressed on the surface of Helper T cells and transmits an inhibitory signal to T cells. The protein contains an extracellular V domain, a transmembrane domain, and a cytoplasmic tail. Alternate splice variants, encoding different isoforms. CTLA4 is similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to CD80 and CD86, also called B7-1 and B7-2 respectively, on antigen-presenting cells. CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal. Intracellular CTLA4 is also found in regulatory T cells and may be important to their function. Fusion proteins of CTLA4 and antibodies (CTLA4-Ig) have been used in clinical trials for rheumatoid arthritis.