Recombinant Human Somatotropin (GH1) is produced in E. coli and spans the full length of the mature protein, covering amino acids 27-217. This product features both an N-terminal 10xHis-tag and a C-terminal Myc-tag to aid in purification and detection. Purity exceeds 90% as verified by SDS-PAGE, making this recombinant protein suitable for various research applications requiring high-quality somatotropin.
Somatotropin, commonly known as growth hormone, plays a crucial role in promoting growth and regulating metabolism. It appears to be involved in numerous biological processes, including stimulating cell growth, reproduction, and regeneration. As an essential component of the growth hormone/insulin-like growth factor axis, somatotropin is of significant interest in research focused on growth disorders, metabolic functions, and related signaling pathways.
Potential Applications
Note: The applications listed below are based on what we know about this protein's biological functions, published research, and experience from experts in the field. However, we haven't fully tested all of these applications ourselves yet. We'd recommend running some preliminary tests first to make sure they work for your specific research goals.
The E. coli expression system lacks the eukaryotic chaperones and post-translational modification machinery necessary for optimal folding of human proteins. GH1 is a hormone with specific structural requirements, including disulfide bond formation, for its biological activity (e.g., binding to the growth hormone receptor, GHR). The presence of two tags, particularly the large N-terminal 10xHis tag, introduces a substantial risk of steric interference that could disrupt the protein's native folding, its ability to form the required disulfide bonds, or its interaction with receptors. While E. coli-derived GH1 can be bioactive, as some studies have reported obtaining active GH1 from E. coli with specific optimization, the absence of validation data for this specific batch means it cannot be assumed to be correctly folded or bioactive. Experimental verification is essential.
1. Antibody Development and Validation Studies
This recombinant GH1 protein is suitable as an immunogen for generating antibodies targeting linear epitopes, as antibody production primarily relies on amino acid sequences rather than native conformation. The dual tagging system provides additional epitopes for antibody screening. The high purity (>90%) reduces contamination risks. However, if the protein is misfolded, antibodies generated may not recognize the native, functionally active GH1 in physiological contexts (e.g., in immunoassays or neutralization studies), particularly if conformational epitopes are critical for recognition. The tags themselves could also induce tag-specific antibodies, requiring careful screening for specificity against the native GH1 sequence
2. Protein-Protein Interaction Studies
The His-tagged GH1 can be used technically in pull-down assays to screen for interaction partners (e.g., growth hormone receptor, GHR). However, the biological relevance of interactions depends entirely on correct folding. Misfolding may alter binding interfaces, leading to non-physiological interactions (false positives) or failure to capture genuine partners (false negatives). The mature protein sequence (aa 27-217) is necessary, but correct folding is paramount for authentic receptor binding. Any interactions identified must be validated using native GH1 from mammalian systems or functional assays.
3. Structural and Biophysical Characterization
The protein’s suitability for high-resolution structural studies (e.g., X-ray crystallography) is strictly dependent on proper folding and homogeneity. Techniques like circular dichroism or dynamic light scattering could be applied, but data from a misfolded protein would not reflect the native structure of GH1. The dual tags, particularly the flexible N-terminal His-tag, could influence results by affecting oligomerization state or spectral properties, potentially leading to misinterpretations. Prior validation of folding (e.g., via size-exclusion chromatography or functional assay) is a prerequisite for meaningful structural insights.
4. ELISA Development and Quantitative Assays
This recombinant GH1 could be used in ELISA development, with the tags facilitating immobilization (His-tag) and detection (Myc-tag). However, the assay's performance and specificity are highly dependent on the protein's folding state. If the protein is misfolded, it may not present native conformational epitopes, potentially leading to reduced sensitivity or specificity in detecting biologically active GH1 in samples. The protein can serve as a standard, but its correlation with native GH1 activity requires confirmation.
5. Cell Culture and Receptor Binding Studies
This application is critically dependent on confirmed bioactivity. GH1's function as a ligand requires precise folding for receptor binding and signaling activation. If the recombinant protein is misfolded or inactive, it would fail to elicit proper cellular responses (e.g., proliferation or signaling), leading to misleading results in dose-response or receptor binding studies. The protein must first be validated in a functional bioassay (e.g., using responsive cell lines like Nb2-11) before use in such experiments.
Final Recommendation & Action Plan
To ensure reliable and meaningful results, it is strongly recommended to prioritize experimental validation of the protein’s folding and bioactivity before committing to any functional application. The action plan should begin with biophysical characterization using size-exclusion chromatography coupled with multi-angle light scattering (SEC-MALS) to assess oligomeric state and monodispersity, and circular dichroism (CD) spectroscopy to analyze secondary structure content against known spectra of bioactive GH1. This should be followed by a functional bioactivity assay, such as a cell proliferation assay using a responsive line (e.g., Nb2-11 rat lymphoma cells), to determine specific activity and compare it to literature values for native GH1. If validation succeeds, the protein can be used confidently for the proposed applications, with appropriate disclosures regarding the tags. If validation fails, its use should be restricted to applications less dependent on native conformation, such as linear-epitope antibody production or as a negative control, with all limitations clearly disclosed in any research communications.
