Insulin-like growth factor binding protein 3, also known as IGFBP3, is a member of the insulin-like growth factor binding protein (IGFBP) family that are cysteine-rich proteins that act as a carrier protein. The protein forms a ternary complex with insulin-like growth factor acid-labile subunit (IGFALS) and either insulin-like growth factor (IGF) I or II. In this form, it circulates in the plasma, prolonging the half-life of IGFs and altering their interaction with cell surface receptors.
Protein Details
Purity
>95% by SDS-PAGE and analyzed by silver stain.
Endotoxin Level
<0.01 EU/µg as determined by the LAL method
Biological Activity
The biological activity of Human IGFBP-3 was determined by its ability to inhibit the biological activity of rhIGF-I or rhIGF-II on MCF-7 cells (Karey, K.P. et al., 1988, Cancer Research 48:4083). The expected ED<sub>50</sub> for this effect is typically 0.05 - 0.15 μg/ml in the presence of 14 ng/ml rhIGF-II.
The predicted molecular weight of Recombinant Human IGFBP-3 is Mr 29 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 37-47 kDa.
Predicted Molecular Mass
29
Formulation
This recombinant protein was lyophilized from a 0.2 μm filtered solution in 30% acetonitrile (CH3CN) and 0.1% trifluoroacetic acid (TFA).
Storage and Stability
This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.
Powered by AI: AI is experimental and still learning how to provide the best assistance. It may occasionally generate incorrect or incomplete responses. Please do not rely solely on its recommendations when making purchasing decisions or designing experiments.
Recombinant Human IGFBP-3 is widely used in research due to its multifaceted roles in regulating cell growth, apoptosis, metabolism, and disease pathophysiology, making it a valuable tool for studies in cancer biology, endocrinology, metabolic disorders, and therapeutic development.
Key scientific applications and advantages include:
Cancer Research: IGFBP-3 inhibits cancer cell growth and can enhance the efficacy of radiation, proapoptotic, and chemotherapeutic agents. It induces apoptosis in certain cancer cells by activating caspase pathways and can specifically target cancer cells when used as a cell-penetrating peptide.
Cell Signaling and Metabolism: IGFBP-3 modulates both IGF-dependent and IGF-independent signaling pathways, affecting cell proliferation, differentiation, and apoptosis. It regulates glucose and lipid metabolism, influences insulin sensitivity, and is involved in hepatic insulin resistance, making it relevant for diabetes and metabolic syndrome studies.
Growth Factor Transport and Stability: As the most abundant IGF-binding protein in human serum, IGFBP-3 stabilizes and transports IGFs, prolonging their half-life and bioactivity. This is crucial for experiments requiring controlled IGF signaling.
Disease Models: IGFBP-3 is implicated in the pathophysiology of diseases such as asthma, ischemia, Alzheimer’s disease, diabetes, and potentially COVID-19, providing a model for studying disease mechanisms and therapeutic interventions.
Bioassays and Functional Studies: Recombinant IGFBP-3 is biologically active and suitable for cell-based assays, enzyme assays, and studies of cell migration, growth, and gene transcription. It can be used to investigate the effects of IGFBP-3 on various cell types and signaling pathways.
Therapeutic Research: IGFBP-3, alone or in complex with IGF-I, has shown clinical benefits in conditions such as growth hormone insensitivity, diabetes, and severe insulin resistance, supporting its use in translational and preclinical studies.
Diagnostic and Monitoring Applications: Measurement of IGFBP-3 levels, often in conjunction with IGF-1, is used to diagnose growth disorders, monitor recombinant growth hormone therapy, and assess metabolic status.
In summary, using recombinant human IGFBP-3 enables precise manipulation of IGF signaling, investigation of cell fate decisions, and modeling of disease processes, making it an essential reagent for diverse biomedical research applications.
Yes, recombinant human IGFBP-3 can be used as a standard for quantification or calibration in ELISA assays, provided that the recombinant protein is of high purity, properly characterized, and its concentration is accurately known. Many commercial ELISA kits for human IGFBP-3, such as those from ScienCell, Boster Bio, and R&D Systems, explicitly use recombinant human IGFBP-3 as the standard to generate the calibration curve needed for quantifying IGFBP-3 in samples.
Key Points:
Recombinant IGFBP-3 as Standard: Recombinant human IGFBP-3 is commonly used in ELISA kits because it is available in a purified, quantifiable form and is immunologically similar to the native protein.
Calibration Curve: The recombinant protein is serially diluted to create a standard curve, which is then used to interpolate the concentration of IGFBP-3 in unknown samples.
Validation: Ensure that the recombinant standard is compatible with the antibodies used in your ELISA system (i.e., it should be recognized by both capture and detection antibodies).
Sample Matrix: When quantifying IGFBP-3 in complex matrices (e.g., serum, plasma), it is important to use a diluent that mimics the sample matrix to minimize matrix effects.
Practical Considerations:
Use the recombinant IGFBP-3 standard according to the manufacturer’s instructions or established protocols.
Always prepare a fresh standard curve for each ELISA run.
Confirm that the recombinant standard is stable and has not undergone degradation or aggregation, which could affect its immunoreactivity.
In summary, recombinant human IGFBP-3 is a suitable and widely used standard for calibrating and quantifying IGFBP-3 in ELISA assays.
Recombinant Human IGFBP-3 has been validated in published research for a range of applications, primarily in bioassays, enzyme assays, and as a tool for studying cell signaling, apoptosis, cancer biology, metabolic regulation, and inflammation.
Key validated applications include:
Bioassays: Recombinant IGFBP-3 is widely used in cell-based bioassays to study its effects on cell proliferation, apoptosis, migration, and differentiation. For example, it has been used to assess its inhibitory effects on melanoma cell growth and invasiveness, as well as its impact on adipogenesis, TGF-β signaling, DNA damage response, and gene transcription.
Enzyme Assays: It has been applied in enzyme assays to investigate its interactions with proteases and its role in proteolytic regulation, particularly in the context of disease states such as diabetes and pregnancy.
In Vivo Studies: Recombinant IGFBP-3 has been administered to animal models (e.g., SCID mice) to evaluate its therapeutic potential in cancer, notably for inhibiting tumor growth and metastasis in melanoma models.
Metabolic and Endocrine Research: It has been used to study its effects on glucose metabolism, insulin sensitivity, and hepatic insulin resistance, both in vitro and in vivo, including hyperinsulinemic clamp studies.
Inflammation and Immune Modulation: IGFBP-3 has been validated for reducing airway inflammation and hyper-responsiveness in respiratory disease models, and for inhibiting monocyte-endothelial adhesion in hyperglycemic conditions.
Cell Signaling and Apoptosis: It is used to dissect IGF-dependent and IGF-independent signaling pathways, including modulation of the Akt-GSK3β pathway, regulation of caspase activation, and protection against TNF-α-induced apoptosis.
Disease Models: Applications extend to models of cancer (colorectal, renal, ovarian, melanoma), diabetes, asthma, ischemia, Alzheimer’s disease, and acute lung injury, where IGFBP-3’s roles in cell growth, apoptosis, and inflammation are investigated.
Clinical Research: While not used directly in patients, recombinant IGFBP-3 is used in research to understand its potential as a therapeutic agent or biomarker for growth disorders, cancer, and metabolic diseases.
Sample types validated include:
Whole cells (cell culture)
Recombinant proteins (for direct biochemical assays)
Cell culture supernatants
Animal models (in vivo studies).
Summary Table: Validated Applications of Recombinant Human IGFBP-3
These applications are supported by numerous peer-reviewed studies and are widely accepted in the scientific community for both mechanistic and translational research.
To reconstitute and prepare Recombinant Human IGFBP-3 protein for cell culture experiments, follow these general guidelines based on manufacturer protocols and best practices:
Reconstitution
Centrifuge the vial before opening to ensure all lyophilized powder is at the bottom.
Reconstitution buffer: Most protocols recommend reconstituting the lyophilized protein in sterile PBS, sterile distilled water, or a specific buffer (e.g., 20 mM acetic acid). The choice depends on the product formulation:
PBS: Use for proteins lyophilized from PBS (e.g., R&D Systems 8874-B3).
Sterile distilled water: Suitable for many recombinant proteins (e.g., Abclonal, Novus Biologicals).
20 mM acetic acid: Some suppliers recommend this for optimal solubility (e.g., Prospec Bio).
Concentration: Reconstitute to a concentration of 100 µg/mL (or as specified by the manufacturer, typically 0.1–1.0 mg/mL).
Gently mix: After adding the buffer, gently swirl or rotate the vial to dissolve the protein. Avoid vigorous shaking to prevent denaturation.
Preparation for Cell Culture
Aliquot and store: Aliquot the reconstituted protein and store at –20°C to –70°C. Avoid repeated freeze-thaw cycles.
Dilution: Dilute the protein in cell culture medium or an appropriate buffer to the desired working concentration just before use.
Sterility: Ensure all steps are performed under sterile conditions to prevent contamination.
Example Protocol
Centrifuge the vial for 1 minute at 1000 × g.
Reconstitute with sterile PBS or sterile distilled water to 100 µg/mL.
Gently mix until fully dissolved.
Aliquot and store at –20°C.
For cell culture, dilute to the required concentration in culture medium.
Notes
Always refer to the specific product datasheet or certificate of analysis for any unique requirements.
Some proteins may benefit from the addition of carrier proteins (e.g., 0.1% BSA) or stabilizers (e.g., 5–50% glycerol) to prevent adsorption and maintain stability.
By following these steps, you can ensure the proper reconstitution and preparation of Recombinant Human IGFBP-3 protein for cell culture experiments.
Products are for research use only. Not for use in diagnostic or therapeutic procedures.
