Recombinant Human LDLR Protein, REH-P01130
Product Introduction
LDLR (Low-Density Lipoprotein Receptor) protein plays a pivotal role in cholesterol homeostasis by binding to low-density lipoprotein (LDL), the major cholesterol-carrying lipoprotein in plasma, and mediating its cellular uptake through receptor-mediated endocytosis. For internalization to occur, receptor-ligand complexes must first cluster into clathrin-coated pits. Beyond its essential function in lipid metabolism, LDLR serves as a receptor for hepatitis C virus (HCV) in hepatocytes during microbial infection, highlighting its dual functionality in cholesterol metabolism and the cellular response to viral infections. This recombinant human LDLR protein comprises the extracellular domain (Ala22-Arg788) of the mature receptor, expressed in HEK293 cells to ensure proper folding, disulfide bond formation, and glycosylation. It is supplied in a tag-free format, preserving its native conformation and biological activity. The protein is suitable for studying LDLR-ligand interactions, PCSK9-mediated receptor regulation, and receptor-mediated endocytosis mechanisms.
Product Features
1. Native-Like Structure: Expressed in HEK293 cells with proper glycosylation and disulfide bond formation, closely recapitulating the native human LDLR extracellular domain.
2. Tag-Free Format: No affinity or fusion tags, preserving native protein conformation and eliminating potential tag-related interference in ligand binding and interaction studies.
3. Biologically Active: Verified to bind Human PCSK9 protein, confirming functional receptor-ligand interaction capability.
4. High Purity: ≥95% as determined by reducing SDS-PAGE.
5. Low Endotoxin: <1 EU/µg, suitable for sensitive cell-based assays and functional studies.
Specifications
Size: 100 µg
Species: Human
Expression Host: HEK293
Protein Construct: Ala22-Arg788 (Extracellular Domain)
Accession: P01130-1
Gene ID: 3949
Tag: Tag Free
Molecular Weight: 85.5 kDa (predicted); Approximately 80-90 kDa and 110-120 kDa under reducing conditions by SDS-PAGE, due to glycosylation
Glycosylation: Yes
Purity: ≥95% as determined by reducing SDS-PAGE
Endotoxin: <1 EU/µg (LAL method)
Form: Sterile lyophilized powder
Formulation: Lyophilized from 0.22 µm filtered PBS, pH 7.4, with 10% trehalose as protectant
Biological Activity: Immobilized Human LDLR, Tag Free at 5 µg/mL (100 µL/well) can bind Human PCSK9 Protein, Avi & His Tag with a linear range of 0.001-0.156 µg/mL.
Storage and Stability
Storage Conditions: Stored at -20°C for 2 years from date of receipt. After reconstitution, stable at 4°C for 1 week or -20°C for longer storage (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.
Shipping Conditions: Room temperature in continental US; may vary elsewhere.
Protocol (For Reference Only)
Important: Centrifuge the vial briefly before opening to collect lyophilized contents. Reconstitute under aseptic conditions. The protein is glycosylated; handle gently.
1. Reconstitution: Reconstitute the lyophilized protein in sterile deionized water to a concentration not less than 100 µg/mL. Allow the solution to sit at room temperature for 10-15 minutes with gentle swirling to ensure complete dissolution. Do not vortex.
2. Long-Term Storage: For long-term storage after reconstitution, add a carrier protein (0.1% BSA, 5% HSA, 10% FBS, or 5% trehalose), aliquot into single-use volumes, and store at -20°C or -80°C. Avoid repeated freeze-thaw cycles.
3. Ligand Binding Assays: For PCSK9 or LDL binding studies, immobilize LDLR protein at 2-10 µg/mL in coating buffer (e.g., PBS or carbonate buffer, pH 9.6) onto ELISA plates. Following blocking, incubate with serial dilutions of PCSK9 or LDL. Detect bound ligand using appropriate detection antibodies or labeled streptavidin for biotinylated ligands.
4. Cellular Uptake Assays: For functional studies, incubate fluorescently labeled LDL (DiI-LDL) with LDLR-expressing cells in the presence or absence of recombinant LDLR as a competitive inhibitor. Quantify cellular LDL uptake by flow cytometry or fluorescence microscopy.
5. PCSK9-Mediated Degradation Studies: Co-incubate recombinant LDLR with PCSK9 protein in vitro, or pre-treat LDLR-expressing cells with PCSK9, and monitor LDLR surface expression by flow cytometry or Western blot.
Precautions
1. Do not reconstitute to a concentration less than 100 µg/mL to avoid protein loss due to non-specific adsorption.
2. For long-term storage of reconstituted protein, addition of a carrier protein is essential to maintain stability.
3. The protein exhibits multiple bands on SDS-PAGE (80-90 kDa and 110-120 kDa) due to differential glycosylation; this is characteristic of HEK293-expressed LDLR.
4. Avoid repeated freeze-thaw cycles; aliquot into single-use volumes after initial reconstitution.
5. For research use only. Not for use in diagnostic or therapeutic procedures.
FAQ (Simplified)
Q1: What region of LDLR does this protein encompass?
A1: This protein comprises the entire extracellular domain of human LDLR (Ala22-Arg788), which includes the ligand-binding domain, EGF precursor homology domain, and O-linked sugar domain. The transmembrane and cytoplasmic domains are not included.
Q2: Why does this protein appear as multiple bands on SDS-PAGE?
A2: LDLR expressed in HEK293 cells undergoes heterogeneous glycosylation, resulting in molecular weight species of approximately 80-90 kDa and 110-120 kDa under reducing conditions. This is characteristic of properly glycosylated LDLR and does not indicate degradation.
Q3: What is the biological activity of this protein?
A3: The immobilized recombinant LDLR protein binds Human PCSK9 Protein (Avi & His Tag) with a linear detection range of 0.001-0.156 µg/mL, confirming functional receptor-ligand interaction.
Q4: How should I store the reconstituted protein?
A4: Reconstituted protein is stable at 4°C for 1 week. For long-term storage, add a carrier protein (0.1% BSA, 5% HSA, or 10% FBS), aliquot into single-use volumes, and store at -20°C or -80°C. Avoid repeated freeze-thaw cycles.
Disclaimer
1. For Research Use Only. Not for use in diagnostic or therapeutic procedures.
2. Due to the variable nature of biological research, optimization of assay conditions is recommended for specific experimental systems.
3. This warranty is limited to the replacement of the product. The manufacturer assumes no liability for incidental or consequential damages, including loss of samples or data.
4. Wear appropriate protective clothing and gloves when handling this product.
Ordering Information
Catalog Number: REH-P01130
Product Name: Recombinant Human LDLR Protein
Size: 100 µg
Price: CNY ¥4630.00 / USD $463.00 / EUR �555.60 / JPY ¥83340.00
2023 Version
