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biovaratropin™ - biosuperior human growth hormone (hGH)

recombinant hGH - biovaratropin™- biosuperior human growth hormone

recombinant hGH

The current trend of human pluripotent stem cell (hPSC) culture systems is to replace animal-derived materials such as FBS, BSA and supportive matrices such a Matrigel/Geltrex, a mouse-derived extracellular matrix, with defined factors in the media.  At NovoHelix, our products are manufactured in the USA using chemically-defined components and, therefore, do not contain manufacturing components such as serum or animal-derived raw materials. Animal-derived materials are complex undefined mixtures and are recognized as significant risks for stable cultivation and clinical application since they have lot-to-lot variations and risk of immunogenic contamination. In addition, the undefined nature of these raw animal products makes it difficult to deconvolute the essential factors that drive growth, maintenance and differentiation programs.

Basic experimentation in early human development is hampered by the paucity of fetal material available to study typical developmental trajectories, by ethical issues associated with using human fetal tissues, and by a dearth of knowledge of the genetic and molecular programs that direct human embryogenesis and gametogenesis.  Therefore, cellular models are a critical resource to understand dysgenesis and to advance our understanding of human infertility.   NovoHelix’ approach to personalized medicine is to develop autologous cell models via epigenetic reprogramming of a patient’s own biopsied cells to pluripotency to create induced pluripotent stem cells (iPSCs). A refined reprogramming procedure using Sendai-viral RNA and pioneer factors such as OCT4/SOX2/KLF4 generates iPSCs akin to human embryonic stem cells (collectively known as hPSCs). When these hPSCs are bathed in media containing the appropriate supportive cues to differentiate into somatic and germ cell lineages, these cell-specific models yield enormous potential to better understand the mechanisms of cell specification.  NovoHelix has manufactured a line of xeno-free cell reagents to support the establishment of clinical-grade human PSCs and to recapitulate some of the dynamic media environments necessary to elucidate key factors to boost our understanding of human development.


Catalog Nr




1 ml
1 mg/ml
10 ml
1 mg/ml
100 ml
1 mg/ml
500 ml
1 mg/ml

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Product Information
Product Literature & Protocol
FAQs & Troubleshooting
Supporting Documents
Product Information
Human growth hormone was improved through protein engineering efforts including directed evolution and rational design.  The final engineered protein was synthesized as a codon-optimized mini-gene and expressed heterologously in an E. coli strain. The engineered protein has physicochemical properties that obviate complex biomanufacturing steps such as protein refolding as a result of increased protein solubility and low isoelectric point (pI) at physiological pH. The recombinant protein was tested and normalized to standard and bespoke activity assays as described below. 

Molecular Weight: 
92.7 kDa

>98 % by SDS-PAGE and PMF + MS/MS. The recombinant hGH protein is manufactured under chemically defined conditions and guaranteed free of animal component reagents, e.g. serum-free, non-xenogeneic. 

Sequence Analysis: 
Each lot of purified recombinant hGH protein was subjected to peptide mass fingerprinting (PMF) by MALDI-TOF/TOF (PMF + MS/MS).

Biological Activity: 
Biovaratropin is evaluated for biological activity using two independent methods: [1] a hypophysectomized (surgical removal of the pituitary gland) animal model for weight gain and [2] a cell line model containing a safe harbor knock-in of a genetic reporter of JAK2-STAT5 signaling activity. 

The somatropin in vivo bioassay exposes hypophysectomized rats to (1) the biovaratropin, (2) the USP somatropin reference standard and (3) a mock injection of excipient as a negative control. The rats are weighed prior to first administration and subsequently weighed again ~18 h after the last subcutaneous injection. Changes in body mass are recorded for each experimental group, e.g. biovaratropin, USP somatotropin and mock injection, and the potency of the biovaratropin relative to the potency of the USP reference standard is computed. Equivalent bioactivity is considered with a potency value of 2 USP somatropin Units/mg or higher with confidence limits of 63%-158% of the calculated potency. In a follow-up experiment, rats received a single subcutaneous dose of biovaratropin or USP somatropin (0, 1, 2.5 or 5.0 mg/kg) during a 30-day window and weight gain was measured on the 31st day. Terminal plasma half-lives of biovaratropin and USP somatropin are 103 h and 3.4 h, respectively.

A cell model bioassay was developed (1) to determine the bioactivity of biovaratropin, (2) to reduce the use of laboratory animal models consistent with best practices and 3R’s, (3) to supplant the aforementioned standard rat in vivo weight gain assay, and (4) to engender a simple, robust and precise bioactivity assay throughout the research, development and manufacture of biovaratropin.  Briefly, ligand binding to the human GHR dimer induces a left-handed crossover conformational change of the GHR transmembrane domains to activate JAK2-STAT5 signaling. The cytokine-responsive transcription factor STAT5 translocates to the nucleus to bind within an engineered genetic reporter circuit that contains multiple copies of sis inducible element (SIE) and interferon γ-activated sequence (GAS) element to drive luciferase expression from a safe harbor locus.   The knock-in luciferase genetic reporter assay is adequate for the determination of biovaratropin bioactivity as the coefficient of variation (CV) for precision, accuracy and linearity were less 7%. Biovaratropin stimulated cell proliferation in a dose-dependent manner with an EC50 310 ng/mL.

Lipopolysaccharide (LPS) was determined by the standard LAL (Limulus amebocyte lysate) test to be < 1 EU/µg.  Due to potential environmental sustainability concerns (collection of the hemolymph used in pharmaceutical testing may negatively affect horseshoe crab populations), a quantitative and more sensitive endotoxin assay was developed using a pyrogen‐testing cell model with knock-in of TLR4/CD14/MD2 at the safe harbor locus AAVS. The TLR4/CD14/MD2 assay is used as an orthogonal screen for LPS in lieu of the LAL method and has a detection limit of 0.005 EU/ml. 

A sterile, aqueous, clear and colorless solution. 

Biovaratropin is supplied at 1 mg/ml in stabilization buffer and remains bioactive for 15 days if maintained refrigerated [2º to 8ºC (35º to 46ºF)]. Stock solutions of biovaratropin can be stored at least 6 months at -20°C and at least 9 months at -80°C. For long term storage, add 0.1% w/v carrier protein such as recombinant human serum albumin (HSA) and avoid repeated freeze-thaw cycles by aliquoting. Lyophilized biovaratropin is stable at least 1 month at 2-8°C.

Biovaratropin is supplied already reconstituted at 1 mg/ml in a stabilization buffer containing 9 mg/mL benzyl alcohol, 5.84 mg/mL sodium chloride, 2 mg/mL polysorbate 20, and 50 mM sodium citrate at a pH of approximately 6.1. The reconstituted solution has been filter sterilized by passing through a 0.22 μm PES membrane.

Disclaimer & Precautions: 
This product is solely for research and development use only and may be subject to conditional use and licensing restrictions. The product shall not be used as an advanced pharmaceutical intermediate (API) or investigational drug or a biologic. This product is not intended to be used as a therapeutic agent or facilitate clinical diagnosis or be used as an in vitro diagnostic (IVD) product. 

The Food and Drug Administration (FDA) and Center for Biologics Evaluation and Research (CBER) define an IVD as: 

“In vitro diagnostic products are those reagents, instruments, and systems intended for use in the diagnosis of disease or other conditions, including a determination of the state of health, in order to cure, mitigate, treat, or prevent disease or its sequelae. Such products are intended for use in the collection, preparation, and examination of specimens taken from the human body. These products are devices as defined in section 201(h)of the Federal Food, Drug, and Cosmetic Act (the act), and may also be biological products subject to section 351 of the Public Health Service Act. Title 21, Code of Federal Regulations (CFR), section 809.3(a).” 

This product shall not be used or formulated in any agricultural, pesticidal, veterinary or animal products, food additives or household chemicals or any other unspecified use.  Please consult the Safety Data Sheet for information regarding hazards and safe handling practices. NovoHelix distributes products for basic and translational research use only. NovoHelix will report any unspecified use to respective regulatory authorities for enforcement to ensure safeguarding of our research products from potential abuse.

Notice to purchaser: 
The purchase price of this product includes a limited, non-transferable license under U.S. and foreign patents or applications owned by NovoHelix to use this product. No other license under these patents or applications is conveyed expressly or by implication by purchase of this product.
Product Literature & Protocol

  • HiFi DNA Assembly Protocol

                                                                                                Recommended Amount of Fragments Used for Assembly

 2–3 Fragment Assembly*4–6 Fragment Assembly**
Positive Control✝
Recommended DNA Molar Ratio
 vector:insert = 1:2 vector:insert = 1:1
Total Amount of Fragments
0.03–0.2 pmols*
X μl
0.2–0.5 pmols**
X μl
10 μl
HiFi DNA Assembly Master Mix
 10 μl10 μl
10 μl
 Deionized H2O10-X μl
 10-X μl0
 Total Volume20 μl✝✝
 20 μl✝✝ 20 μl
Optimized cloning efficiency is 50–100 ng of vector with 2-fold excess of inserts.
Use 5 times more insert if size is less than 200 bp. Total volume of unpurified PCR fragments in the assembly reaction should not exceed 20%.

**To achieve optimal assembly efficiency, design ≥ 20 bp overlap regions between each fragment with equimolarity (suggested: 0.05 pmol each).

Control reagents are provided for 5 experiments.

†† If greater numbers of fragments are assembled, increase the volume of the reaction linearly by using additional NovoHelix HiFi DNA Assembly Master Mix. Alternatively, pool the DNA fragments into an equimolar mix first and then re-purify these pooled equimolar fragments over a micro-column and elute with a minimum volume (~10-µl). The eluate may be reapplied to the same micro-column  membrane to improve elution of large DNA fragments without increasing the final volume..

Recommended Storage Condition:   
This assembly mixture can be stored at -20 °C for at least one year.  The enzymes remain active following at least 10 freeze-thaw cycles.
FAQs & Troubleshooting
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1: Ranke MB, Wit JM. Growth hormone - past, present and future. Nat Rev Endocrinol. 2018 May;14(5):285-300. doi: 10.1038/nrendo.2018.22. Epub 2018 Mar 16. Review. PubMed PMID: 29546874.

1: Waters MJ, Brooks AJ. Growth hormone and cell growth. Endocr Dev. 2012;23:86-95. doi: 10.1159/000341761. Epub 2012 Nov 23. Review. PubMed PMID: 23182823.

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1: England CG, Ehlerding EB, Cai W. NanoLuc: A Small Luciferase Is Brightening Up the Field of Bioluminescence. Bioconjug Chem. 2016 May 18;27(5):1175-1187. doi: 10.1021/acs.bioconjchem.6b00112. Epub 2016 Apr 19. Review. PubMed PMID: 27045664PubMed Central PMCID: PMC4871753.

1: Zimmer B, Piao J, Ramnarine K, Tomishima MJ, Tabar V, Studer L. Derivation of  Diverse Hormone-Releasing Pituitary Cells from Human Pluripotent Stem Cells. Stem Cell Reports. 2016 Jun 14;6(6):858-872. doi: 10.1016/j.stemcr.2016.05.005. PubMed PMID: 27304916; PubMed Central PMCID: PMC4912387.

1: Suga H. Making pituitary hormone-producing cells in a dish [Review]. Endocr J. 2016 Aug 31;63(8):669-80. doi: 10.1507/endocrj.EJ16-0232. Epub 2016 May 28.  Review. PubMed PMID: 27245938.

1: Bozzola M, Zecca M, Locatelli F, Radetti G, Pagani S, Autelli M, Tatò L, Chatelain P. Evaluation of growth hormone bioactivity using the Nb2 cell bioassay in children with growth disorders. J Endocrinol Invest. 1998 Dec;21(11):765-70. PubMed PMID: 9972677.

1: Maimaiti M, Tanahashi Y, Mohri Z, Fujieda K. Development of a bioassay system for human growth hormone determination with close correlation to immunoassay. J Clin Lab Anal. 2012 Sep;26(5):328-35. doi: 10.1002/jcla.21527. PubMed PMID: 23001977; PubMed Central PMCID: PMC6807445.

1: Chen WY, Wight DC, Mehta BV, Wagner TE, Kopchick JJ. Glycine 119 of bovine growth hormone is critical for growth-promoting activity. Mol Endocrinol. 1991 Dec;5(12):1845-52. PubMed PMID: 1791834.

1: Borromeo V, Sereikaite J, Bumelis VA, Secchi C, Scirè A, Ausili A, D'Auria S,  Tanfani F. Mink growth hormone structural-functional relationships: effects of renaturing and storage conditions. Protein J. 2008 Apr;27(3):170-80. PubMed PMID: 18080174.

1: Oliveira NA, Cecchi CR, Higuti E, Oliveira JE, Jensen TG, Bartolini P, Peroni  CN. Long-term human growth hormone expression and partial phenotypic correction by plasmid-based gene therapy in an animal model of isolated growth hormone deficiency. J Gene Med. 2010 Jul;12(7):580-5. doi: 10.1002/jgm.1470. PubMed PMID: 20603861.

1: Khan MA, Sadaf S, Sajjad M, Waheed Akhtar M. Production enhancement and refolding of caprine growth hormone expressed in Escherichia coli. Protein Expr Purif. 2009 Nov;68(1):85-9. doi: 10.1016/j.pep.2009.05.011. Epub 2009 May 27. PubMed PMID: 19477280.

1: de Boer EN, van der Wouden PE, Johansson LF, van Diemen CC, Haisma HJ. A next-generation sequencing method for gene doping detection that distinguishes low levels of plasmid DNA against a background of genomic DNA. Gene Ther. 2019 Aug;26(7-8):338-346. doi: 10.1038/s41434-019-0091-6. Epub 2019 Jul 11. PubMed PMID: 31296934; PubMed Central PMCID: PMC6760532.

1: Wang R, Zhang JY, Lu KH, Lu SS, Zhu XX. Efficient generation of GHR knockout Bama minipig fibroblast cells using CRISPR/Cas9-mediated gene editing. In Vitro Cell Dev Biol Anim. 2019 Dec;55(10):784-792. doi: 10.1007/s11626-019-00397-6. Epub 2019 Aug 27. PubMed PMID: 31456163.

1: Holt RIG, Ho KKY. The Use and Abuse of Growth Hormone in Sports. Endocr Rev. 2019 Aug 1;40(4):1163-1185. doi: 10.1210/er.2018-00265. PubMed PMID: 31180479.

1: Ikeda M, Wada M, Fujita Y, Takahashi S, Maekawa K, Honjo M. A novel bioassay based on human growth hormone (hGH) receptor mediated cell proliferation: measurement of 20K-hGH and its modified forms. Growth Horm IGF Res. 2000 Oct;10(5):248-55. PubMed PMID: 11042021.

1: Yao W, Yu L, Fan W, Shi X, Liu L, Li Y, Qin X, Rao C, Wang J. A Cell-Based Strategy for Bioactivity Determination of Long-Acting Fc-Fusion Recombinant Human Growth Hormone. Molecules. 2019 Apr 9;24(7). pii: E1389. doi: 10.3390/molecules24071389. PubMed PMID: 30970583; PubMed Central PMCID: PMC6479951.

1: Dehkhoda F, Lee CMM, Medina J, Brooks AJ. The Growth Hormone Receptor: Mechanism of Receptor Activation, Cell Signaling, and Physiological Aspects. Front Endocrinol (Lausanne). 2018 Feb 13;9:35. doi: 10.3389/fendo.2018.00035. eCollection 2018. Review. PubMed PMID: 29487568; PubMed Central PMCID: PMC5816795.
Supporting Documents

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