Recombinant Protein Definition

Recombinant protein is a manipulated form of protein, which is generated in various ways to produce large quantities of proteins, modify gene sequences and manufacture useful commercial products. The formation of recombinant protein is carried out in specialized vehicles known as vectors. Recombinant technology is the process involved in the formation of recombinant protein.

Recombinant Protein is a protein encoded by a gene — recombinant DNA — that has been cloned in a system that supports expression of the gene and translation of messenger RNA (see expression system). Modification of the gene by recombinant DNA technology can lead to expression of a mutant protein. Proteins coexpressed in bacteria will not possess post-translational modifications, e.g. phosphorylation or glycosylation; eukaryotic expression systems are needed for this.

Recombinant DNA (rDNA) molecules are DNA sequences that result from the use of laboratory methods (molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms. Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure; they differ only in the sequence of nucleotides within that identical overall structure. Consequently, when DNA from a foreign source is linked to host sequences that can drive DNA replication and then introduced into a host organism, the foreign DNA is replicated along with the host DNA.
Proteins that result from the expression of recombinant DNA within living cells are termed recombinant proteins. When recombinant DNA encoding a protein is introduced into a host organism, the recombinant protein will not necessarily be produced. Expression of foreign proteins requires the use of specialized expression vectors and often necessitates significant restructuring of the foreign coding sequence.

Biologics International Corp (BIC) provides our esteemed clients with the rapid, high quality, and cost-effective recombinant protein production services. We offer manufacturing as well as wild type, mutant, and ortholog proteins. Our services could advance your project from gene synthesis to protein expression, purification, and stable cell line construction. Till date, we have successfully delivered 2000+ recombinant proteins (enzymes, cytokines, growth factors, hormones, receptors, transcription factors, antibodies, antibody fragments, etc.), which have been widely used in antibody preparation, enzyme activity assay, in vivo efficacy evaluation, in vitro diagnosis, as well as vaccine screening and other applications.

Choose BIC as your reliable partner for your protein research, and we can help you accelerate your discovery in a timely and cost-effective manner at every step of the way, and at a very affordable price. Contact us today to speak with our protein specialists.

Protein Expression and Purification Service

Bacterial protein expression

Bacterial Expression System	Details	Time
Gene Cloning and Expression Test
Strategy design	We will design optimal plan according to customer’s demands and protein’s characteristics.	1 day
Codon optimization	We optimize the codon to maximize the expression level	1~2 weeks
Gene synthesis
Subcloning gene into expression vector	Strains selected for each project, all common expression strains are available
Expression strain construction and small scale test		2 weeks
Pilot Scale Expression and Purification
Expression optimization & bacterial cell culture	Deliverables: 1~5mg protein (soluble, >85% purity), Cloning vector, QC data and final report.	2~3 weeks
Multiple-step protein purification		2~3 weeks
Additional Services
Large-Scale production	High Cell Density Fermentation (HCDF) up to 500L with 23-130g cell/L	3~5 weeks
Endotoxin removal	<0.01-1.0 EU/ug, including endotoxin detection (LAL assay) and endotoxin removal Triton (X-114 phase separation,etc)	1~2 weeks
Metabolic labeling	Stable isotope labeling (¹³C, ¹⁵N ), protein biotinylation, etc.	1~2 weeks
Tag-Free	Enzymatic cleavage methods and Self-cleaving enzymatic methods are available	1~2 weeks
High-throughput Protein Expression	Our high throughput capability enables us to obtain large quantities of highly purified proteins in a short time	Customized according to your project
Lyophilization	1 day

NOTE:

The size of target protein you provide is preferably less than 100 kD. If not, please contact us.
Generally, we provide the expression and purification of the protein with specific labels (HIS/GST/SUMO..)
We also provide proteins expression without tags or tag removing service, but it needs extra charge.
We guarantee the stability and solubility of proteins, but not the biological and functional properties of proteins.
If the protein expresses as inclusion bodies, refolding will be done to make the protein soluble. And if you don’t want the renaturation, also we can provide SupernateIN_TM and acquire proteins from the supernatant.

Mammalian cell expression system

Mammalian Expression System	Details	Time
Codon optimization	Cloning vector	3 weeks
Gene synthesis
Plasmid construction
*Transient Transfection Expression*
Transfection-grade DNA prep	1mg protein (soluble, >90% purity)	1~2 weeks
1L HEK293 or CHO cell culture		2 weeks
Transient transfection expression
Multiple purification		1 week
QA/QC		1 week
Large scale production	Customized according to your project
*Stable Cell Line Development*
Killing curve test & Transfection optimization	QC & delivery of cell pools (Optional 1) QC & delivery of single cell clones (Optional 2)	3~4 weeks
Cell preparation
Transient expression evaluation
Stable transfection		6~8 weeks
Positive clones/cell pool screening
Screen and scale up the positive clones
MTX/MSX amplification	QC & Delivery of single cell clones (Optional 3)	7~8 weeks
Sub-cloning & single cell clones screening
Scale-up the positive single cell clones
QC
Batch culture	QC reports
Stability test
Mycoplasma test
Identify and freeze stable Single Cell Clones

Yeast expression system

Yeast Expression System	Time
Gene Cloning and Expression Test
Strategy design	1 day
Codon optimization	2~3weeks
Gene synthesis
Subcloning gene into expression vector
Construction of P. pastoris multicopy integrant strain	4~5 weeks
Small scale protein expression and optimization
Pilot Scale Expression and Purification
1-2L Yeast cell culture	2~3 weeks
1-5mg protein (soluble, >80% purity)
Large Scale Production
Protein production to kilogram scale/gram-scale	4~7 weeks

Insect cell expression system

Insect Cell Expression System	Time
Gene Cloning and Expression Test
Strategy design	1 day
Codon optimization	2~3weeks
Gene synthesis
Subcloning gene of interest into baculovirus transfer vector
Prepare recombinant bacmid DNA	3~4 weeks
Baculovirus titration	3~4 weeks
Pilot Scale Expression and Purification
Transfect insect cells, generate P1 and P2 baculovirus stock	3~4 weeks
Pilot scale protein expression and purification（500 ml culture)
1mg protein (soluble, > 80% purity)

Quality Control

Service Options	Details
PAGE	Denaturing, reducing, non-reducing, densitometry (Bio-Rad ChemiDoc XRS+)
Concentration	Dye binding assay, A280, RP-HPLC
Western Blot	Anti-Tag or Anti-Target, Colorimetric or chemiluminescence (ChemiDoc XRS+)
Analytical SEC	Standard or client-specific methods
Reverse Phase HPLC	Standard or client-specific methods, purity and/or concentration measurement
Mass Spec	Whole protein mass by MALDI or ESI, in-gel digest, LC-MS/MS, by qualified partner
Activity Assay	Absorbance, fluorescence, luminescence (Cuvette to 384-well plate)
ELISA	Anti-tag or anti-target, host cell protein, commercial or custom
Others	Inquire

Next: Soluble Protein Test Introduction and Method