# Recombinant Protein Definition: How Scientists Engineer Proteins


## Key Takeaways

- A recombinant protein is synthesized by a host cell that has been engineered to express a gene from a different source, enabling the production of proteins not naturally present or in insufficient quantities within that host. This process leverages the universal genetic code and the host's intrinsic transcription and translation machinery.
- The production workflow involves isolating the gene of interest, inserting it into an expression vector containing essential regulatory elements like promoters and origins of replication, transforming this vector into a suitable host cell, and inducing protein expression.
- Host cell selection is critical, with *Escherichia coli* being cost-effective for simple proteins but lacking eukaryotic post-translational modifications like glycosylation, while mammalian cells (e.g., CHO, HEK293) are necessary for complex modifications essential for therapeutic efficacy.
- Purification of recombinant proteins commonly employs affinity chromatography, utilizing tags such as polyhistidine (His-tag) for binding to immobilized metal ions, followed by elution with imidazole, and verification of identity and purity via SDS-PAGE and Western blotting.
- Recombinant protein technology underpins numerous medical therapeutics, including human insulin and monoclonal antibodies, vital research tools like Green Fluorescent Protein (GFP), and industrial enzymes used in detergents and food processing.
- Common challenges in recombinant protein production include protein misfolding leading to insoluble inclusion bodies, particularly in bacterial systems, and the absence of essential eukaryotic post-translational modifications such as complex glycosylation, which necessitates the use of more sophisticated host systems.

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A recombinant protein is a protein whose [amino acid sequence](/blog/guides/amino-acid-sequence) is encoded by a recombinant DNA molecule—that is, DNA assembled in the laboratory from genetic material originating from more than one source. In practice, this means taking a gene of interest from one organism, inserting it into a piece of carrier DNA called a vector, and introducing that construct into a host cell that does not naturally carry the gene. The host cell's own machinery then reads the foreign gene and synthesizes the corresponding protein. The resulting product is functionally identical to the protein the original organism would have made, provided the host cell processes it correctly.

The power of this approach lies in its universality. Because the genetic code is nearly identical across all life forms, a human gene placed inside a bacterium can direct the synthesis of a human protein. This principle underpins the production of human insulin, therapeutic antibodies, vaccines, industrial enzymes, and countless research reagents. Understanding how recombinant proteins are made requires a working knowledge of gene expression, host cell biology, and protein biochemistry—each of which we will examine in turn.

## The Central Dogma: From DNA to Protein

To appreciate what a recombinant protein is, you must first understand how cells normally convert genetic information into protein. The flow of information in all living cells follows [the central dogma of molecular biology](/blog/news/the-central-dogma-of-molecular-biology): DNA is transcribed into RNA, and RNA is translated into protein.

### DNA as the Blueprint

Deoxyribonucleic acid (DNA) is a double-stranded polymer composed of four nucleotide building blocks: adenine (A), thymine (T), guanine (G), and cytosine (C). The sequence of these nucleotides along a gene encodes the instructions for building a protein. A gene is a contiguous stretch of DNA that contains the coding sequence for a polypeptide, along with regulatory elements that control when and how much of that polypeptide is made.

Transcription is the first step. An enzyme called RNA polymerase binds to a promoter—a specific DNA sequence upstream of the coding region—and synthesizes a single-stranded messenger RNA (mRNA) molecule complementary to the template strand of the gene. In eukaryotic cells, this primary transcript undergoes processing: introns (non-coding regions) are spliced out, a 5' cap is added, and a poly-A tail is appended to the 3' end. The mature mRNA then exits the nucleus and travels to the cytoplasm, where translation occurs.

### Ribosomes and Protein Synthesis

Translation is carried out by ribosomes, large ribonucleoprotein complexes that read the mRNA sequence in groups of three nucleotides called codons. Each codon specifies one amino acid. Transfer RNA (tRNA) molecules, each carrying a specific amino acid, recognize their cognate codon through complementary base pairing and deliver the amino acid to the growing polypeptide chain. The ribosome catalyzes peptide bond formation between successive amino acids, elongating the chain until it encounters a stop codon (UAA, UAG, or UGA), at which point translation terminates and the completed polypeptide is released.

The newly synthesized polypeptide must then fold into its three-dimensional structure, often with the assistance of molecular chaperones, and may undergo post-translational modifications such as glycosylation, phosphorylation, or disulfide bond formation. Only after these steps does the protein become biologically active.

For a recombinant protein, this entire pathway is commandeered. The gene of interest is placed under the control of regulatory sequences that the host cell recognizes, and the host's own [transcription and translation](/knowledge/molecular-biology/transcription-translation) machinery produces the protein. The key difference from native gene expression is that the gene originates from a different organism or is otherwise manipulated in the laboratory.

## How Recombinant Proteins Are Made

The production of a recombinant protein follows a standardized workflow. Each step requires specific molecular tools and careful design choices that determine yield, solubility, and biological activity.

1. **Gene isolation.** The DNA sequence encoding the protein of interest is obtained. This can be done by [polymerase chain reaction](/knowledge/molecular-biology/polymerase-chain-reaction) (PCR) amplification from genomic DNA or cDNA (complementary DNA synthesized from mRNA), by chemical synthesis of the gene, or by excision from another plasmid. For eukaryotic genes containing introns, cDNA is typically used because bacteria cannot splice out introns.

2. **Vector construction.** The gene is inserted into a plasmid vector—a small, circular double-stranded DNA molecule that can replicate independently within the host cell. The vector contains several essential elements: an origin of replication (ori) for [plasmid replication](/knowledge/molecular-biology/plasmid-replicate-independently), a selectable marker (usually an antibiotic resistance gene) to identify cells that have taken up the plasmid, and a [multiple cloning site](/knowledge/diagnostics/molecular/multiple-cloning-site-plasmids-structure-function) (MCS) containing unique restriction enzyme recognition sequences where the gene is inserted. The gene is placed downstream of a promoter that drives its expression.

3. **Transformation.** The recombinant plasmid is introduced into host cells. For bacteria, this is typically done by heat shock or electroporation. Heat shock involves incubating cells with plasmid DNA on ice, briefly raising the temperature to 42°C to increase membrane permeability, and then returning the cells to ice. Electroporation uses a brief electrical pulse to create transient pores in the cell membrane. Successfully transformed cells are selected by plating on medium containing the appropriate antibiotic.

4. **Protein expression.** Transformed cells are grown in liquid culture, and expression of the recombinant gene is induced. The induction method depends on the promoter system used. For the widely used T7/lac system in *E. coli*, expression is induced by adding isopropyl β-D-1-thiogalactopyranoside (IPTG) at a final concentration of 0.1–1 mM when the culture reaches an optical density at 600 nm (OD₆₀₀) of 0.4–0.8. The culture is then incubated for 3–6 hours at 37°C, or overnight at lower temperatures (16–25°C) to improve protein solubility.

5. **Harvesting and purification.** Cells are lysed by mechanical disruption (e.g., sonication or French press) or enzymatic digestion (lysozyme), and the recombinant protein is purified from the lysate using techniques described in the purification section below.

### Choosing a Host Cell

The choice of host organism is the single most important decision in recombinant protein production. The host must be able to fold the protein correctly, perform any required post-translational modifications, and produce the protein in sufficient quantity. No single host is ideal for all proteins, and the selection depends on the protein's complexity, size, and intended use.

For simple proteins that require no glycosylation and fold correctly in the reducing environment of the bacterial cytoplasm, *Escherichia coli* is the default choice. For larger, more complex proteins requiring disulfide bonds or glycosylation, eukaryotic hosts such as yeast, insect cells, or mammalian cells are necessary. The trade-off is cost and complexity: bacterial systems are inexpensive and fast, while mammalian systems are slow and expensive but produce the most authentic proteins.

### [Expression Vectors](/knowledge/molecular-biology/expression-vector) and Promoters

The promoter is a DNA sequence that RNA polymerase recognizes to initiate transcription. For recombinant protein production, the promoter must be strong (driving high levels of transcription) and ideally inducible (allowing the researcher to control when expression begins). Constitutive promoters drive continuous expression, which can be toxic to the host if the protein is harmful or burdensome to produce.

Common inducible promoter systems include:

- **T7 promoter/lac operator (E. coli):** Recognized by T7 RNA polymerase, which is provided by a lysogenic phage (DE3) integrated into the host chromosome. The lac operator represses transcription until IPTG is added.
- **araBAD promoter (E. coli):** Induced by L-arabinose and repressed by glucose. Allows tight regulation and graded expression levels.
- **GAL1 promoter (yeast):** Induced by galactose and repressed by glucose. Used in *Saccharomyces cerevisiae*.
- **Metallothionein promoter (mammalian cells):** Induced by heavy metals such as zinc or cadmium.
- **Tetracycline-inducible system (mammalian cells):** Uses a tetracycline-responsive transactivator to drive expression in the presence or absence of doxycycline.

The choice of promoter affects not only yield but also the kinetics of expression. Fast, strong induction can lead to protein aggregation, while slower induction may allow proper folding.

## Common Host Systems for Protein Production

Different host organisms offer distinct advantages and limitations. The table below summarizes the key characteristics of the major expression systems.

| Host System | Typical Yield | Glycosylation | Disulfide Bonds | Cost | Time Scale | Best For |
|---|---|---|---|---|---|---|
| *E. coli* (bacteria) | High (1–5 g/L) | None | Poor in cytoplasm; possible in periplasm | Low | Days | Simple proteins, enzymes, antigens |
| *S. cerevisiae* / *P. pastoris* (yeast) | High (0.1–10 g/L) | High-mannose type | Yes | Low–moderate | Days–weeks | Secreted proteins, some therapeutics |
| Insect cells (baculovirus) | Moderate (1–500 mg/L) | Simple, non-sialylated | Yes | Moderate | Weeks | Complex proteins, virus-like particles |
| Mammalian cells (CHO, HEK293) | Low–moderate (0.01–1 g/L) | Human-like, complex | Yes | High | Weeks–months | Therapeutic antibodies, complex glycoproteins |
| Plant cells / transgenic plants | Variable | Plant-specific | Yes | Low–moderate | Months | Vaccines, industrial enzymes |

### Bacterial Systems (E. coli)

*Escherichia coli* remains the most widely used host for recombinant protein production. Its advantages are numerous: rapid growth to high cell densities, inexpensive culture media, well-characterized genetics, and a vast toolkit of expression vectors and strains. A typical culture can reach an OD₆₀₀ of 2–5 in a few hours, and yields of 1–5 grams of protein per liter of culture are achievable for well-expressed proteins.

However, *E. coli* has significant limitations. As a prokaryote, it cannot perform glycosylation, and it lacks the machinery for complex disulfide bond formation in the cytoplasm. The cytoplasmic environment is reducing, which prevents the formation of disulfide bonds that are essential for the stability of many eukaryotic proteins. Proteins that require such bonds can sometimes be directed to the periplasm—the space between the inner and outer membranes—where the environment is oxidizing and disulfide bond formation is possible.

Another major issue is the formation of inclusion bodies. When a eukaryotic protein is expressed at high levels in *E. coli*, it often misfolds and aggregates into insoluble particles. These inclusion bodies can sometimes be solubilized with denaturants such as 8 M urea or 6 M guanidine hydrochloride and then refolded by gradual removal of the denaturant, but this process is inefficient and often yields inactive protein. Strategies to improve soluble expression include lowering the induction temperature, using weaker promoters, co-expressing molecular chaperones, and fusing the target protein to solubility-enhancing tags such as maltose-binding protein (MBP) or glutathione S-transferase (GST).

### Mammalian Cell Systems

When a protein requires human-like post-translational modifications—particularly complex N-linked glycosylation—mammalian cells are the host of choice. Chinese hamster ovary (CHO) cells and human embryonic kidney (HEK) 293 cells are the most common. These cells secrete properly folded, glycosylated proteins into the culture medium, simplifying purification.

The cost is substantial. Mammalian cells grow slowly, require complex media supplemented with serum or defined growth factors, and are sensitive to shear stress and metabolic byproducts. Yields are typically lower than bacterial systems, although modern fed-batch processes can achieve 1–10 g/L for monoclonal antibodies. The development of a stable production cell line can take months, and the culture process itself requires weeks.

Despite these challenges, mammalian systems are indispensable for biopharmaceuticals. Approximately 70% of approved recombinant protein therapeutics are produced in CHO cells, including monoclonal antibodies, erythropoietin, and coagulation factors. The human-like glycosylation patterns of these proteins are critical for their stability, half-life, and immunogenicity profile in patients.

## Purification and Characterization

Once the host cells have produced the recombinant protein, it must be separated from the thousands of other proteins and cellular components present in the lysate or culture medium. This purification process typically involves multiple chromatography steps, each exploiting a different physical or chemical property of the target protein.

### Affinity Tags

The most powerful purification strategy is affinity chromatography, which relies on a specific interaction between the target protein and a ligand immobilized on a column matrix. To enable this, recombinant proteins are often engineered with an affinity tag—a short peptide or protein domain fused to the N- or C-terminus of the target.

The most common tag is the polyhistidine tag (His-tag), consisting of six to ten consecutive histidine residues. Histidine has a high affinity for immobilized metal ions such as nickel (Ni²⁺) or cobalt (Co²⁺). In immobilized metal affinity chromatography (IMAC), the cell lysate is passed over a column containing Ni²⁺-nitrilotriacetic acid (Ni-NTA) agarose. The His-tagged protein binds to the column, while untagged proteins flow through. After washing with buffer containing a low concentration of imidazole (10–20 mM) to remove non-specifically bound proteins, the target is eluted with a higher imidazole concentration (200–500 mM), which competes with the histidine residues for metal binding.

Other common tags include:

- **GST tag:** Fused to glutathione S-transferase, which binds to glutathione-conjugated agarose. Elution is achieved with reduced glutathione (10–20 mM).
- **MBP tag:** Maltose-binding protein binds to amylose resin and is eluted with maltose (10 mM).
- **FLAG tag:** An eight-amino-acid peptide (DYKDDDDK) recognized by a specific monoclonal antibody. Elution is achieved with a competing FLAG peptide or low pH.

Affinity tags can be removed after purification using site-specific proteases such as tobacco etch virus (TEV) protease, which recognizes the sequence ENLYFQG and cleaves between Q and G. This leaves the target protein with minimal or no additional amino acids.

### SDS-PAGE and Western Blot

After purification, the protein must be verified for identity, purity, and integrity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is the standard method for assessing purity and molecular weight. In SDS-PAGE, the protein is denatured with SDS, an anionic detergent that binds to the polypeptide chain and imparts a uniform negative charge proportional to protein length. The denatured proteins are then electrophoresed through a polyacrylamide gel matrix, where they separate by size—smaller proteins migrate faster. After electrophoresis, the gel is stained with Coomassie Brilliant Blue or silver stain, and the protein bands are visualized. A single band at the expected molecular weight indicates a pure preparation.

Western blotting (immunoblotting) confirms the identity of the protein. The proteins from an SDS-PAGE gel are transferred electrophoretically to a nitrocellulose or polyvinylidene fluoride (PVDF) membrane. The membrane is incubated with a primary antibody that specifically recognizes the target protein, followed by an enzyme- or fluorophore-conjugated secondary antibody that binds to the primary antibody. Detection via chemiluminescence or fluorescence confirms that the protein of interest is present and runs at the expected size.

Additional characterization methods include mass spectrometry for exact molecular weight determination and sequence verification, circular dichroism spectroscopy for secondary structure assessment, and functional assays to confirm biological activity.

## Real-World Applications of Recombinant Proteins

Recombinant protein technology has transformed medicine, research, and industry. The ability to produce human proteins in controlled laboratory systems has made possible therapies that were previously unimaginable.

### Medical Therapeutics

The first recombinant protein approved for human use was human insulin (Humulin), produced in *E. coli* and approved by the U.S. Food and Drug Administration in 1982. Before this, insulin for diabetic patients was extracted from the pancreases of pigs and cattle, which differed slightly in [amino acid sequence](/blog/guides/amino-acid-sequence) from human insulin and could trigger immune responses. Recombinant human insulin is identical to the endogenous protein and is now produced on a massive scale.

Other major recombinant therapeutics include:

- **Erythropoietin (EPO):** Stimulates red blood cell production; used to treat anemia in kidney disease and chemotherapy patients.
- **Human growth hormone (hGH):** Treats growth hormone deficiency in children.
- **Monoclonal antibodies:** Used to treat cancers (e.g., trastuzumab for HER2-positive breast cancer), autoimmune diseases (e.g., adalimumab for rheumatoid arthritis), and infectious diseases (e.g., palivizumab for RSV).
- **Blood clotting factors:** Factor VIII and Factor IX for hemophilia.
- **Vaccines:** Recombinant hepatitis B surface antigen and human papillomavirus (HPV) L1 protein self-assemble into virus-like particles that elicit protective immune responses.

### Research Tools

Recombinant proteins are indispensable in basic research. Green fluorescent protein (GFP), originally isolated from the jellyfish *Aequorea victoria*, is now produced recombinantly and used as a reporter gene to visualize gene expression, protein localization, and cell lineage in living organisms. Recombinant enzymes such as Taq polymerase (from *Thermus aquaticus*) and restriction enzymes are used daily in molecular biology laboratories. Recombinant cytokines and growth factors are used to culture cells and study signaling pathways.

The ability to engineer recombinant proteins with specific mutations has enabled structure-function studies that reveal how protein sequence determines structure and activity. Site-directed mutagenesis—introducing specific amino acid changes into a cloned gene—allows researchers to test hypotheses about catalytic residues, binding sites, and regulatory domains.

### Industrial Applications

Beyond medicine and research, recombinant proteins are used in industrial processes. Recombinant enzymes are used in:

- **Detergents:** Proteases and lipases that break down protein and fat stains.
- **Food processing:** Chymosin (rennet) for cheese making, amylases for starch conversion, and glucose isomerase for high-fructose corn syrup production.
- **Biofuels:** Cellulases and hemicellulases that break down plant biomass into fermentable sugars.
- **Textiles:** Cellulases for stone-washing denim and amylases for fabric desizing.

These industrial enzymes are typically produced in *E. coli* or fungi such as *Aspergillus* and *Trichoderma*, which can secrete large quantities of protein into the culture medium.

## Common Pitfalls and Misconceptions

Students new to recombinant protein technology often encounter several conceptual and practical difficulties. Understanding these pitfalls is essential for interpreting experimental results and designing successful expression strategies.

### Misfolding and Inclusion Bodies

The most common practical problem in recombinant protein production is protein misfolding. When a protein is expressed at high levels, the cellular folding machinery (chaperones and foldases) can become overwhelmed, and the nascent polypeptide chains aggregate into insoluble inclusion bodies. This is particularly problematic in *E. coli*, where the reducing cytoplasmic environment prevents disulfide bond formation and the lack of eukaryotic chaperones hampers folding of complex proteins.

Inclusion bodies are visible as dense, refractile granules in the cell cytoplasm. They consist of aggregated, partially folded protein that is biologically inactive. While inclusion bodies can be solubilized with strong denaturants and refolded in vitro, the refolding process is often inefficient, with yields of correctly folded protein typically below 20%. Strategies to avoid inclusion body formation include:

- Reducing the expression temperature to 16–25°C to slow protein synthesis and allow more time for folding.
- Using a weaker promoter or lower inducer concentration to reduce the rate of protein synthesis.
- Co-expressing molecular chaperones such as GroEL/GroES or DnaK/DnaJ.
- Fusing the target protein to a highly soluble partner such as MBP or NusA.
- Targeting the protein to the periplasm, where the oxidizing environment supports disulfide bond formation.

### Post-Translational Modifications

Many eukaryotic proteins require post-translational modifications for full biological activity. The most important of these is glycosylation—the covalent attachment of sugar chains to asparagine (N-linked) or serine/threonine (O-linked) residues. Glycosylation affects protein folding, stability, half-life, and immunogenicity.

*E. coli* cannot glycosylate proteins at all. Yeast can glycosylate, but it adds high-mannose sugar chains that differ from human glycosylation and can be immunogenic in humans. Insect cells add simpler sugar chains that lack sialic acid, resulting in glycoproteins with short half-lives in the bloodstream. Only mammalian cells produce glycosylation patterns that closely match those of human proteins.

This is why therapeutic glycoproteins such as monoclonal antibodies and EPO are produced in mammalian cells despite the higher cost. For research purposes, however, the absence of glycosylation may be acceptable if the protein's function does not depend on it.

### Misconceptions About Recombinant DNA vs. Recombinant Protein

A common conceptual error is confusing recombinant DNA with recombinant protein. Recombinant DNA refers to the artificially constructed DNA molecule itself—the plasmid or viral vector containing the gene of interest. Recombinant protein is the protein product encoded by that DNA and produced by the host cell. The distinction matters because the DNA construct is the tool, while the protein is the product. When scientists say they are "expressing a recombinant protein," they mean they have introduced recombinant DNA into a host and induced the host to produce the protein.

Another misconception is that recombinant proteins are "unnatural" or fundamentally different from native proteins. In fact, a properly expressed and folded recombinant protein is chemically and functionally identical to the native protein. The amino acid sequence is the same, and the three-dimensional structure is the same. The only difference is the production method.

A third misconception is that all recombinant proteins are produced in bacteria. While *E. coli* is the most common host, many proteins—especially those requiring glycosylation—are produced in yeast, insect, or mammalian cells. The choice of host is dictated by the protein's requirements, not by convenience.

## Summary: Key Takeaways

- A recombinant protein is a protein produced from a gene that has been artificially inserted into a host cell, allowing the host's machinery to synthesize a protein from another organism.
- The process involves gene isolation, vector construction, transformation into a host, and induction of protein expression.
- The choice of host system—bacterial, yeast, insect, or mammalian—determines the protein's folding, post-translational modifications, yield, and cost.
- Affinity tags such as His-tags enable rapid purification, while SDS-PAGE and Western blotting verify protein identity and purity.
- Recombinant proteins are used in medicine (insulin, antibodies, vaccines), research (GFP, enzymes), and industry (detergents, biofuels).
- Common challenges include protein misfolding, inclusion body formation, and the absence of appropriate post-translational modifications in simpler host systems.

## Frequently Asked Questions

### What is a recombinant protein in simple terms?

A recombinant protein is a protein made by a cell that has been given a foreign gene in the laboratory. The cell reads the gene and builds the protein, just as it would build its own proteins. This allows scientists to produce human proteins in bacteria or other easily grown cells.

### How are recombinant proteins produced?

The gene encoding the protein is inserted into a plasmid vector, which is introduced into host cells. The cells are grown in culture, and expression of the gene is induced. The protein is then extracted from the cells or culture medium and purified using techniques such as affinity chromatography.

### What are recombinant proteins used for?

Recombinant proteins are used as therapeutic drugs (insulin, growth hormone, monoclonal antibodies), vaccine components, research reagents (enzymes, fluorescent proteins), and industrial enzymes (detergents, food processing, biofuels).

### Why are recombinant proteins important?

Recombinant proteins allow the production of human proteins in large quantities without relying on human or animal sources. This has made life-saving therapies affordable and accessible, enabled the development of vaccines, and provided researchers with tools to study protein function.

### What is the difference between recombinant DNA and recombinant protein?

Recombinant DNA is the artificially constructed DNA molecule containing the gene of interest. Recombinant protein is the protein product encoded by that DNA and synthesized by the host cell. The DNA is the blueprint; the protein is the final product.

### What host cells are used for recombinant protein production?

Common hosts include *E. coli* (bacteria), *Saccharomyces cerevisiae* and *Pichia pastoris* (yeast), insect cells infected with baculovirus, and mammalian cells such as CHO and HEK293. Plants and transgenic animals are also used for specialized applications.

### Can recombinant proteins be made in plants?

Yes. Plants such as tobacco, rice, and maize can be genetically engineered to produce recombinant proteins. This approach, called molecular farming, is used for vaccine antigens, antibodies, and industrial enzymes. Plant systems offer low production costs and scalability, though glycosylation patterns differ from humans.

## Further Reading

- Barnes LM, Bentley CM, Dickson AJ. *Molecular definition of predictive indicators of stable protein expression in recombinant NS0 myeloma cells*. Biotechnology and bioengineering. 2004. [PubMed 14704993](https://doi.org/10.1002/bit.10893)
- Marschall L, Sagmeister P, Herwig C. *Tunable recombinant protein expression in E. coli: enabler for continuous processing?*. Applied microbiology and biotechnology. 2016. [PubMed 27170324](https://doi.org/10.1007/s00253-016-7550-4)
- Nordin F, Ahmad RNR, Farzaneh F. *Transactivator protein: An alternative for delivery of recombinant proteins for safer reprogramming of induced Pluripotent Stem Cell*. Virus research. 2017. [PubMed 28408207](https://doi.org/10.1016/j.virusres.2017.04.007)
- Tang B et al. *Molecular definition and characterization of recombinant bovine CB8 and CB10: immunogenicity and arthritogenicity*. Clinical immunology (Orlando, Fla.). 1999. [PubMed 10479530](https://doi.org/10.1006/clim.1999.4755)
- Rivoire B et al. *Chemical definition, cloning, and expression of the major protein of the leprosy bacillus*. Infection and immunity. 1994. [PubMed 7910593](https://doi.org/10.1128/iai.62.6.2417-2425.1994)
- Liang M et al. *Generation of an HFRS patient-derived neutralizing recombinant antibody to Hantaan virus G1 protein and definition of the neutralizing domain*. Journal of medical virology. 2003. [PubMed 12436484](https://doi.org/10.1002/jmv.10259)

## Related Topics

- [Express Recombinant Protein](/knowledge/molecular-biology/express-recombinant-protein)
- [Recombinant Protein Lab](/knowledge/molecular-biology/recombinant-protein-lab)
- [Recombinant Protein Laboratory](/knowledge/molecular-biology/recombinant-protein-laboratory)
- [Contract Recombinant Protein Expression](/knowledge/molecular-biology/contract-recombinant-protein-expression)
- [Recombinant Protein Expression System](/knowledge/molecular-biology/recombinant-protein-expression-system)

## Related Clinical & Scientific Guides

* [MAPK Pathway: Mechanism, Function, and Clinical Relevance](/knowledge/molecular-biology/mapk-pathway)
* [Mammalian Cell Culture Bioreactors: A Practical Guide](/knowledge/molecular-biology/mammalian-cell-culture-bioreactor)
* [Nucleotide Formation: Biosynthesis and Assembly of DNA/RNA Building Blocks](/knowledge/molecular-biology/nucleotide-formation)