Mammalian Protein Expression
QYAOBIO provides different mammalian protein expression for customers in worldwide
Mammalian protein expression systems are suitable for the most mammalian proteins with native structure and activity, due to the physiologically relevant environment. This kind of systems result in high level of post-translational processing and functional activity. This kind of expression system is commonly applied for production of antibodies, therapeutic proteins, or functional proteins for cell-based assays.
Mammalian expression systems are preferred for the production mammalian proteins, and applied for the production of antibodies, complex proteins, and proteins in functional cell-based assays. However, all these advantages are coupling with more demanding culture conditions than other expression systems.
Mammalian Expression Process
Mammalian expression systems can produce proteins transiently, or through stable cell lines. Transient production can generate large quantity of protein in 1 to 2 weeks, while stable cell-lines can be applied over several experiments. Furthermore, comparing to other expression systems, mammalian systems provide more native folding and post-translational modifications in proteins. There are 3 different mammalian expression system for recombinant proteins.
HEK293 Expression Systems
HEK293 cells are applied extensively for transient expression of recombinant proteins. These cell lines have ease of culture and efficient transfection rates, this make it suitable for custom protein production in researches.
CHO Expression Systems
CHO cells are prominent in stable expression, stable transfection in CHO cell lines are most suitable for high-yielding recombinant protein production in mammalian hosts. CHO cells are adaptable to diverse culture conditions, their secretory features also make the purification to be relatively easy.
The common process of Mammalian Expression Systems:
Gene synthesis & Codon Optimization
- Systematic optimization of leading codon
- Analysis and optimization of rare codons, codon bias, or other factors
Vector Construction
- Clone target genes into the expression vectors
- Plasmid sequencing and preparation
Protein Expression and Purification
- Transfection of HEK293/CHO cells
- Optimize expression condition and evaluate protein expression
- Different protein purification technologies
Additional Service
- Tag removal
- Endotoxin removal
- Activity assay
- Protein analysis
Quality Control
- Western blot
- Mass spectrometry
Mammalian Expression for Recombinant Proteins
Mammalian cell-based expression is the dominant system for recombinant protein production. It is able to handle complex post-translational modifications, folding and assembly of recombinant proteins, in order to achieve superior protein complexes than other systems.
There are two methods for recombinant protein production in mammalian cells: stably transfected cell lines, transiently transfected cell lines.
- Stably transfected cell lines can express the recombinant protein continuously with high yields. However, the creation of stable cell lines will take up several month to complete.
- Transient transfection is applied for small-scale to large-scale expression cultures. Recent improvements can increase yields from milligram to gram. Transient transfection methods have the shorter time-frame from DNA delivery to protein harvest.
| Category | Specification |
| Stable transfection | Transient transfection and selection for stably transfected cells Cell line development for stable cell pools Screening and expansion of high-expressing single clone |
| Transient transfection | Subclone gene into suitable mammalian cell transient expression vector Transient transfection, expression evaluation, and optimization |
Advantage of Mammalian Expression Systems
- Transient expression is easy and rapid
- Correct post-translational modifications and proper folding found in mammalian cells
- Stable transfection systems have higher yield, scalability, reproducible production
- Excellent for secreted and membrane proteins
Disadvantage of Mammalian Expression Systems
- The cost is expensive
- Difficult to scale up production
- Low yield in production of intracellular proteins
- Long expression time for stable transfection
Applications of Mammalian Expression Systems
- Production of monoclonal antibody
- Production of urokinase
- Production of follicle stimulating hormone
- RNA interference
Mammalian expression Options
In order to produce functional mammalian proteins with appropriate posttranslational modifications, like disulfide bonds, glycosylation, and phosphorylation. QYAOBIO provides flexible options for mammalian protein expression
Mammalian Transient Protein Expression
Mammalian transient protein expression can provide flexible and rapid protein production. This technique is ideal for expression of human, and other mammalian proteins. Due to its specific generation of proteins with native folding and post-translational modifications (like glycosylation). while other systems are difficult to achieve.
- FreeStyle 293 System
- Expi293 System
- ExpiCHOSystem
Stable Cell Line Development
QYAOBIO applies different stable cell engineering platform to accelerate every project. Our various technologies allow you to select the best method to fit desired timeline.
- Flp-In™ System
- Jump-In™ System
Constitutive Mammalian Protein Expression
Constitutive mammalian systems apply powerful expression vector to deliver high protein yields. This enables exceptionally high levels of recombinant protein production in adherent-or suspension-adapted mammalian cells. The main characteristics including:
- Nearly five-time higher protein yields
- Fast, simple high efficient with time saving cloning
- Ideal for antibody production and structural biology
- Ideal for stable mammalian expression
- Complete kit for the necessary cloning reagents
Membrane Protein Expression Systems
Membrane protein expression is challenging in mammalian systems, it is difficult to preserve the correct conformation of proteins in isolation from native environment. Therefore, QYAOBIO provides different membrane expression systems to deliver membrane proteins efficiently and reliably.
- High yield: increase membrane protein yields
- Simplify workflow: no enzymatic or mechanical dissociation
- Scalability: simplified scale up without multiple flasks
- Versatility: multiple formats to suit different protein classes
Inducible Mammalian Protein Expression
Inducible mammalian expression systems can control the protein expression by utilizing CMV promoters and tetracycline resistance operons. This will repress and derepress transcription effectively. These cell lines exhibit low basal expression in the repressed state ,and high expression in induction with tetracycline.
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