Product Description
Human B7 homolog 3 (B7-H3) is a member of the B7 family of immune proteins that provide signals for the regulation of immune responses. Other family members include B7-1, B7-2, B7-H1/PD-L1, B7-H2, and PD-L2. B7 family proteins are type I transmembrane immunoglobulin (Ig) superfamily members that contain extracellular Ig V-like and Ig C-like domains with a short cytoplasmic tail. Among the family members there is about 20 - 40% amino acid (aa) sequence identity. B7-H3 was initially reported to be a 316 aa type I transmembrane precursor protein that contained a signal sequence, an extracellular region with one V-type and one C-type Ig domain, a transmembrane segment and a short cytoplasmic tail. Subsequent studies have identified a second 110 kDa form whose precursor is 534 aa in length. Termed 4IgB7-H3 or B7-H3b, this molecule has two additional Ig-like domains (one Vtype and one C-type) and shows a ubiquituous expression pattern. It would appear that the human 4Ig form is the principal, if not the only form of B7-H3. Its precursor contains a 26 aa signal sequence, a 435 aa extracellular region, a 31 aa transmembrane domain, and a 42 aa cytoplasmic tail. The four Ig-like domains alternate between V-type and Ctype, and apparently are the consequence of a V-C type tandem duplication. B7-H3b is expressed on dendritic cells as well as activated T, B and NK cells.
Specifications
| Synonyms | B7-H3; CD276; PSEC0249; 4Ig-B7-H3; UNQ309; PRO352; B7 homolog 3; CD276 Uniprot No. Q5ZPR3.1 |
| Source | Recombinant Human B7-H3 (4Ig)/B7-H3b Protein is expressed from HEK293 Cells with hFc tag at the C-terminal. It contains Gly27-Thr461. |
| Molecular Weight | Approximately 73.4 kDa. Due to glycosylation, the protein migrates to 80-110 kDa based on Tris-Bis PAGE result. |
| Purity | > 95% as determined by SDS-PAGE and HPLC. |
| Formulation | Lyophilized from 0.22 μm filtered solution in PBS (pH 7.4). Normally 5% trehalose is added as protectant before lyophilization. |
| Endotoxin | < 1.0 EU per 1μg of the protein by the LAL method. |
| Reconstitution | Centrifuge tubes before opening. Reconstituting to a concentration more than 100 μg/mL is recommended (usually we use 1 mg/mL solution for lyophilization). Dissolve the lyophilized protein in distilled water. |
| Activity | ELISA Data: Immobilized Human B7-H3 (4Ig) , hFc Tag at 5μg/ml (100μl/Well) on the plate. Dose response curve for Biotinylated Anti-B7-H3 Antibody, hFc Tag with the EC50 of 44.3ng/ml determined by ELISA. |
Storage
The product should be stored at -20~-80℃ for 1 year from date of receipt. 2-7 days, 2 ~8 °C under sterile conditions after reconstitution. 3-6 months, -20~-80℃ under sterile conditions after reconstitution. Recommend to aliquot the protein into smaller quantities when first used and avoid repeated freeze-thaw cycles.
Notes
1. Avoid repeated freezing and thawing. 2. Please operate with lab coats and disposable gloves, for your safety. 3. This product is for research use only.