Recombinant Human Hemopexin Protein: Properties & Applications

Recombinant Human Hemopexin Protein is a recombinantly produced form of the high-affinity heme-binding plasma glycoprotein that plays a central role in heme scavenging, cytoprotection against oxidative stress, and acute-phase inflammatory responses.

Protein Name

Recombinant Human Hemopexin Protein

Biological Function

High-affinity heme scavenging; transports free heme to the liver for catabolism and prevents heme-mediated oxidative damage

Protein Class

Acute-phase plasma glycoprotein

Primary Source Organism

Human (Homo sapiens)

Key Research Areas

Heme metabolism, inflammation, hemolytic disease, oxidative stress, cytoprotection

SKU

rp365790

What Is Hemopexin? Biological Background

Hemopexin (HPX) is a plasma glycoprotein primarily synthesized by hepatocytes and, to a lesser extent, by neurons and retinal cells. It belongs to the family of acute-phase proteins whose circulating levels rise significantly in response to infection, inflammation, or tissue injury. The defining feature of hemopexin is its extraordinarily high affinity for free heme (protoporphyrin IX–iron complex), which is among the highest known for any protein–ligand interaction.

Free heme released during hemolysis or cell damage is highly cytotoxic: it intercalates into lipid bilayers, generates reactive oxygen species (ROS), and can trigger inflammatory signaling. Hemopexin neutralizes these dangers by binding free heme with very high affinity and transporting the heme–HPX complex to the liver, where it is internalized via the LRP1 (CD91) receptor on hepatocytes and macrophages. Heme is then catabolized by heme oxygenase-1 (HO-1), releasing iron, carbon monoxide, and biliverdin.

Understanding hemopexin biology is therefore critical for researchers studying hemolytic anemias, sickle cell disease, transfusion medicine, ischemia-reperfusion injury, and sepsis.

Biochemical Properties of Recombinant Human Hemopexin Protein

Recombinant Human Hemopexin Protein is produced using recombinant DNA technology to replicate the native human HPX sequence. The native protein contains two homologous beta-propeller domains connected by a linker region; heme binds between these two domains via bis-histidyl axial coordination. The protein is a monomer under physiological conditions.

Key biochemical characteristics include:

• Glycosylation: Native hemopexin is an N-glycosylated protein. The glycosylation pattern of recombinant HPX depends on the expression system used (e.g., mammalian, insect, or E. coli). Mammalian cell-expressed recombinant HPX most closely mimics native glycosylation and folding.
• Molecular Weight: The mature native protein has an apparent molecular weight that can vary depending on glycosylation; the protein core is encoded by a single-chain polypeptide.
• Heme Binding: Hemopexin binds heme in a 1:1 stoichiometry with very high affinity, effectively sequestering it from the oxidative milieu.
• Stability: Recombinant HPX should be stored according to supplier specifications, typically at -20°C or -80°C, and freeze-thaw cycles should be minimized to maintain activity.

Researchers should verify lot-specific purity, endotoxin levels, and biological activity data provided in the Certificate of Analysis (CoA) prior to use in sensitive assays.

Research Applications

Recombinant Human Hemopexin Protein supports a broad range of research applications across biochemistry, cell biology, and translational medicine:

• Heme Toxicity and Cytoprotection Studies: Recombinant HPX is used as a tool to scavenge extracellular heme in cell culture models, allowing researchers to dissect the specific contribution of free heme to oxidative injury, apoptosis, and inflammatory signaling.
• Hemolytic Disease Models: In models of sickle cell disease, malaria, or hereditary hemolytic anemias, recombinant HPX is employed to study the protective role of the heme-scavenging system and to evaluate potential therapeutic interventions.
• ELISA and Immunoassay Standards: High-purity recombinant HPX serves as a calibration standard or positive control in sandwich ELISA and other immunoassay formats designed to quantify HPX in plasma or serum samples.
• Receptor Binding and Internalization Studies: Recombinant HPX enables the characterization of LRP1/CD91-mediated endocytosis pathways and can be used in binding assays, competition experiments, and receptor mapping studies.
• Biomarker Research: As circulating HPX levels are altered in conditions such as sepsis, liver disease, and hemolysis, recombinant protein supports development and validation of diagnostic biomarker assays.
• Structural and Biophysical Studies: Purified recombinant HPX facilitates crystallography, NMR, or cryo-EM studies aimed at understanding heme-binding domain architecture and conformational changes upon heme binding.

Handling, Storage, and Quality Considerations

Proper handling and storage of Recombinant Human Hemopexin Protein are essential to preserve its structural integrity and biological activity:

• Storage Temperature: Store at the temperature specified in the product datasheet, typically -20°C for short-term and -80°C for long-term storage. Avoid repeated freeze-thaw cycles by preparing single-use aliquots upon first thaw.
• Reconstitution: If supplied lyophilized, reconstitute in sterile, ultrapure water or the buffer recommended by the supplier. Allow the vial to equilibrate to room temperature before opening, and mix gently without vortexing.
• Endotoxin Testing: For cell-based assays, confirm endotoxin levels (EU/mg) from the CoA to avoid confounding LPS-driven inflammatory responses.
• Purity Assessment: SDS-PAGE and HPLC purity data should be reviewed. High-purity preparations (typically ≥90% by SDS-PAGE) are recommended for functional assays.
• Carrier Protein: Some formulations include BSA as a carrier protein to improve stability. If BSA interferes with downstream assays, select a BSA-free formulation.
• Working Concentrations: Optimal working concentrations should be empirically determined for each assay system. Consult published literature and the product datasheet for initial guidance.

Why Choose Aladdin Scientific Recombinant Human Hemopexin Protein?

Aladdin Scientific offers Recombinant Human Hemopexin Protein (SKU: rp365790) to support rigorous, reproducible research. Key advantages include:

• Defined Specification: Each lot is characterized with purity, molecular identity, and activity data provided in an accompanying Certificate of Analysis.
• Research-Grade Quality: Manufactured under controlled conditions to meet the demands of biochemical, cell biological, and assay development workflows.
• Reliable Supply: Aladdin Scientific maintains inventory to support consistent sourcing for ongoing research programs and multi-site studies.
• Technical Support: Researchers can access application guidance, protocol recommendations, and expert consultation to optimize experimental outcomes.

For ordering information, pricing, and availability, visit the Aladdin Scientific product page for SKU rp365790 or contact our technical support team.

Frequently asked questions

What is the primary biological function of Hemopexin?

Hemopexin is the plasma protein with the highest known affinity for free heme. Its primary function is to bind and sequester free heme released during hemolysis or cellular damage, transport it to the liver via the LRP1/CD91 receptor, and thereby prevent heme-mediated oxidative damage and inflammation.

What expression systems are used to produce Recombinant Human Hemopexin Protein?

Recombinant Human Hemopexin Protein can be produced in mammalian cell systems (which best replicate native glycosylation), insect cell systems (baculovirus expression), or prokaryotic systems such as E. coli (which yield non-glycosylated protein). The choice of expression system affects glycosylation pattern, folding, and functional activity, so researchers should select based on the requirements of their specific application.

How should I store Recombinant Human Hemopexin Protein to maintain activity?

Store Recombinant Human Hemopexin Protein at -20°C for short-term use or at -80°C for long-term storage. To minimize activity loss, prepare single-use aliquots immediately after the first thaw and avoid repeated freeze-thaw cycles. Always refer to the specific storage instructions provided in the product datasheet and Certificate of Analysis.

Can Recombinant Human Hemopexin Protein be used as an ELISA standard?

Yes, high-purity Recombinant Human Hemopexin Protein is commonly used as a calibration standard or positive control in sandwich ELISA kits and other immunoassay formats for measuring hemopexin concentrations in biological samples such as plasma or serum. Confirm antibody cross-reactivity with the recombinant form before use.

What diseases or conditions are associated with altered Hemopexin levels?

Hemopexin levels are decreased in conditions involving significant hemolysis, such as sickle cell disease, malaria, and hemolytic anemias, as the protein is consumed while scavenging free heme. Elevated levels may be observed as part of the acute-phase response during infection or inflammation. Altered HPX levels have also been reported in sepsis, liver disease, and certain neurological conditions.

References

1. Tolosano E, Altruda F. Hemopexin: structure, function, and regulation. DNA Cell Biol. 2002;21(4):297-306.
2. Hvidberg V, Maniecki MB, Jacobsen C, Højrup P, Møller HJ, Moestrup SK. Identification of the receptor scavenging hemopexin-heme complexes. Blood. 2005;106(7):2572-2579.
3. Vinchi F, Tolosano E. Therapeutic approaches to limit hemolysis-driven endothelial dysfunction: scavenging free heme to preserve vascular homeostasis. Oxid Med Cell Longev. 2013;2013:396527.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.