Mammalian Cell Expression System


Mammalian Cell Expression

The prokaryotic expression system has the advantages of high expression level, simple operation, short cycle, easy large-scale and high-density culture and low cost. For the full-length antibody and glycoprotein biological drug, the folding of expression product polypeptide chain, the disulfide bond, the presence or absence of glycosylation and the type of glycosylation often affect the properties of the synthesis, secretion, biological activity, in vivo stability, and immunogenicity of the expressed product. Compared with other eukaryotic expression systems, the expression of the target gene in mammalian cells is similar to that of the native protein in the type and manner of the glycosylation, and can be correctly assembled into the multi-subunit protein.


  • No self-produced endotoxin
  • Secretion expression is available
  • With a variety of complex N-linked glycosylation, accurate O-linked glycosylation and other post-translational processing
  • Close to native protein in the molecular structure, physical and chemical properties and biological functions
  • High yield after system optimization: as high as 100 mg/L
  • Multi-cell lines, multi-expression methods to improve the protein expression success rate and protein yield
  • Price as low as $1280/1mg, delivery time as short as 35 business days


CUSABIO Protein service Guarantee

Risk-free: We do NOT charge if we cannot deliver the protein.

Note: This risk-free custom protein service is only suitable for proteins within 800aa. We will charge according to different steps if you need to express proteins more than 800aa.

Service Process:

Steps Project Process Cusabio Features Lead Time
1 Plasmid construction Plasmid construction Codon optimization; gene synthesis Multiple vectors optimization, More options for customers
In order to improve the success rate of expression and achieve higher yield, in addition to conventional N-terminal fusion protein expression, we also provide C-terminal fusion protein, which retains the bioactivity of the protein while ensuring high purity.
15-20 business days
The PCR amplification products are ligated to the vectors e.g. pSec series, pCMV series and pcDNA series vectors
Transform TOP10 E.coil competent cells
Obtain the correct recombinant plasmid
2 Small scale expression Small scale expression Prepare the transfection grade recombinant plasmid in large quantities Optimization of transfection conditions
Set different transfection conditions, select the optimal experimental conditions according to the test results.
9-11 business days
Transient transfect HEK293, CHO and other cells
Detect expression products
3 Scale up expression and purificationScale up expression and purification Scale up the culture cells and transfect Multi-condition expression scheme
According to the protein localization and the best experimental conditions in the small test expression, select different cell lines and different ways of transfection, which can increase the expression quantity, greatly improve the protein expression.
8-9 business days
Explore different chromatographic conditions including ion exchange, hydrophobic and others by using AKTA, and then determine the optimal purification method.
4 Additional services (Optional)Additional protein services Charge Tag removal by restriction digestion Flexible additional services
Customers can flexibly choose from a variety of additional services to their specific needs, e.g. Endotoxin removal, Filter-sterilization, Tag removal, Lyophilization, etc. Some are complimentary, and some require additional charge.
3 business days
Free Filter-sterilization; Endotoxin removal; Lyophilization (Note: Lyophilization and Filter-sterilization can not be met simultaneously) 2 business days
5 Quality ControlProtein Quality Control Testing of purity, concentration, etc. QC report is provided. Detailed COA report
Detailed product data sheet and COA are provided for each project.
3-5 business days
Total lead time 35-45 business days

Case 1
It is well known that the expression yield of mammalian cells is relatively low, the protein was optimally expressed with our mammalian expression system, the target band can be observed by SDS-PAGE analysis of the culture supernatants. The purified protein expression level can up to 10 mg/L. The theoretical molecular weight of the protein was 42 kDa, and the protein is modified with glycosylation by SDS-PAGE, which was confirmed by the examination of LC-MS/MS.

Mammalian Cell Expression case 01
  • Lane 1:Flow through
  • Lane 2:Culture medium stoste
  • Lane 3:Marker
  • Lane 4:20 mM imidazole elution
  • Lane 5:60 mM imidazole elution

Case 2
Three full-length antibodies were transfected into CHO cells using our vector, after SDS-PAGE detection, the bands were observed in the supernatant of the culture medium, the expressed level was up to 100 mg/L.

Mammalian Cell Expression case 02
  • Lane 1:Antibody 1 culture medium stoste
  • Lane 2:Antibody 1 flow through
  • Lane 3:Antibody 1 elution
  • Lane 4:Antibody 2 culture medium stoste
  • Lane 6:Marker
  • Lane 7:Antibody 2 elution
  • Lane 8:Antibody 3 culture medium stoste
  • Lane 9:Antibody 3 flow through
  • Lane 10:Antibody 3 elution

Characteristic expression systems

pSecTag2A-JT Vector+HEK293 Cell efficient expression

pSecTag2A-JT Vector
  • 1.

    Carrys CMV strong promoter, containing IgK signal peptide which can enhance the secretory quantity of the protein

  • 2.

    Compared with conventional 6xHis tag, the N-terminal 10xHis tag has a stronger binding ability in IMAC. Meanwhile the thrombin site makes it easy to remove the tag to obtain untagged protein.

  • 3.

    The C-terminal MYC-tag can be used for WB detection, and it has stronger sensitivity compared with His-tag.

  • 4.

    Amp resistance screening.

CUSABIO Protein Expression Quotation Request Form

I.Your Information

  • Name*

    This field is required.

  • Email*

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  • Country*

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II.Product Information

  • Product Name (including species)*

    This field is required.

  • Uniprot No*

    This field is required.

  • Order Quantity

    This field is required.

  • Expression System

    This field is required.

  • Expression Region

    This field is required.

  • Sequence

    This sequence does not include the Tag sequence. Please fill if you have special demand.

  • Do you need tag ?

    Tag Removal Service

    If customer needs to remove the tag, please remark with tag removal service, otherwise, we won't remove the tag.

    There are extra charges for tag removal service. The cost will be list in the quotation.

    Not all protein tags can be removed as some proteins will be very unstable after tag removal.

    If we fail in removing the tag, we won’t charge for any extra cost, and remark this information in COA as follows “Note: The laboratory determined that the Tag on your protein could not be removed with standard laboratory procedures. Your protein is being supplied with the Tag intact.”

    Generally, the delivery time will be extended for 2-3 days.

    This field is required.

  • Molecular Weight

  • Application*

    This field is required.

III.Customer's Requirement(Click here to show more)

  • Tag Removal Service

  • Endotoxin Level Requirement

  • Aseptic Manufacture Processing

  • Western Blot Service

  • Purity Requirement

  • Concentration Requirement

  • Storage Buffer Requirement

  • Delivery Form Requirement

  • Package Size Requirement

  • Other Requirement

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