For the best experience on the Abcam website please upgrade to a modern browser such as Google Chrome

Hello. We're improving abcam.com and we'd welcome your feedback.

Hello. We're improving abcam.com and we'd welcome your feedback.

Infomation icon

We haven't added this to the BETA yet

New BETA website

New BETA website

Hello. We're improving abcam.com and we'd welcome your feedback.

Take a look at our BETA site and see what we’ve done so far.

Switch on our new BETA site

Now available

Search and browse selected products

  • A selection of primary antibodies

Purchase these through your usual distributor

In the coming months

  • Additional product types
  • Supporting content
  • Sign in to your account
  • Purchase online
United States
Your country/region is currently set to:

If incorrect, please enter your country/region into the box below, to view site information related to your country/region.

Call (888) 77-ABCAM (22226) or contact us
Need help? Contact us

  • My account
  • Sign out
Sign in or Register with us

Welcome

Sign in or

Don't have an account?

Register with us
My basket
Quick order
Abcam homepage

  • Research Products
    By product type
    Primary antibodies
    Secondary antibodies
    ELISA and Matched Antibody Pair Kits
    Cell and tissue imaging tools
    Cellular and biochemical assays
    By product type
    Proteins and Peptides
    Proteomics tools
    Agonists, activators, antagonists and inhibitors
    Cell lines and Lysates
    Multiplex Assays
    By research area
    Cancer
    Cardiovascular
    Cell Biology
    Epigenetics
    Metabolism
    Developmental Biology
    By research area
    Immunology
    Microbiology
    Neuroscience
    Signal Transduction
    Stem Cells
  • Customized Products & Partnerships
    Customized Products & Partnerships

    Customized products and commercial partnerships to accelerate your diagnostic and therapeutic programs.

    Customized products

    Partner with us

  • Support
    Support hub

    Access advice and support for any research roadblock

    View support hub

    Protocols

    Your experiments laid out step by step

    View protocols

  • Events
    • Conference calendar
    • Cancer
    • Cardiovascular
    • Epigenetics & Nuclear signaling
    • Immunology
    • Neuroscience
    • Stem cells
    • Tradeshows
    • Scientific webinars
    Keep up to date with the latest events

    Full event breakdown with abstracts, speakers, registration and more

    View global event calendar

  • Pathways
    Cell signalling pathways

    View all pathways

    View all interactive pathways

Glossary: protein products

Related

  • Proteins and peptides

    Key terms associated with our range of proteins. 

    Contents

    • Protein product grading
    • Recombinant proteins
    • Purity and validation​
    • Expression and species


    Protein product grading


    Premium grade bioactive 
    Cytokines that are of the highest activity and validation, perfect for preclinical cell culture and functional studies. ​These recombinant proteins are produced consistently to exceed our stringent thresholds. 

    Key features of these premium-grade proteins include:

    • Optimal bioactivity
    • Mammalian expressed
    • Ultra-high purity confirmed by LC/MS (>95%) and SDS-PAGE (>99%)
    • Ultra-low endotoxin (<0.005 EU per µg)
    • Size confirmed by mass spectrometry
    • Animal free
    • Carrier free
    • Manufactured to ISO9001

    Bioactive grade
    Recombinant proteins that are bioactivity validated, ideal for cell culture and functional studies. ​

    Key features of bioactive-grade products include:

    • Validated bioactivity
    • Mammalian, E.coli, insect, yeast, or wheat germ expression
    • High purity (>90%) confirmed by SDS-PAGE
    • Endotoxin level below <1 EU per µg
    • Size confirmed by SDS-PAGE​

    Research grade
    These are recombinant proteins that are non-bioactive, for use as standards within western blot, flow cytometry, and other experiments. 

    Key features of research-grade proteins include:

    • Mammalian, E.coli, insect, yeast or wheat germ expression
    • Purity analyzed (>80%) by SDS-PAGE
    • Size confirmed by SDS-PAGE


    ​Recombinant proteins


    Recombinant protein
    A protein produced using recombinant DNA sequences acting as templates from which proteins are expressed in various expression systems via the processes of transcription and translation. When bioactivity has been confirmed they are also classed as being in a "native-like" state. 


    Native protein
    A protein isolated from endogenous samples such as blood or animal tissue. They are in their folded and assembled form and haven’t been altered by heat, chemicals, enzyme reaction, or other denaturants.


    Denatured protein
    A protein that has lost its native folded structure. Denatured proteins are produced by altering the folding conditions, which can include increased temperature, altering buffer pH, or adding denaturants. Denatured proteins typically lose their biological function; however, the action of denaturation can be reversed in many cases.


    Post-translational modifications (PTMs)
    Modifications made to proteins after they have been synthesized, including phosphorylation, glycosylation, ubiquitination, nitrosylation, methylation, acetylation, lipidation, and proteolysis. Post-translational modifications can have many roles, including mediating proper protein folding or stability, directing a nascent protein to distinct cellular compartments, activating or inactivate catalytic activity, or otherwise influencing the biological activity of the protein.


    Bioactivity
    The response that a protein elicits within a biological system. The specific bioactivity of a protein is a measured using a functional assay and expressed as the ED50: the effective dose required to produce a biological response in 50% of a population. Not all proteins sold have bioactivity validated as it is not required for some applications.



    Purity and validation


    Purity
    The percentage of the supplied product that is the protein of interest. Protein purity can be determined by multiple methods including SDS-PAGE, liquid chromatography (LC), and mass spectrometry (MS). The most accurate measurement of purity can be made using LC and MS together.


    Animal-free
    A protein is animal-free if has been produced without the use of any animal-derived materials.


    Carrier-free
    A protein is carrier-free if it provided to the customer without a carrier protein. Carrier proteins such as BSA are often added to proteins for stability; however, researchers often require carrier-free products for cell culture and in vivo use.


    Endotoxin level
    ​Endotoxins are bacterial toxins which may be present as contaminants within protein products. The LAL method is a standard method of measuring endotoxins. Endotoxin levels tend to be higher in proteins expressed using E.coli than those expressed in other systems.



    ​Expression and species


    Expression system
    ​Expression systems are the biological hosts used to generate recombinant proteins. Sources used include bacteria, yeast, insect, and mammalian expression systems. Recombinant proteins can also be expressed using cell-free systems such as wheat germ extract.


    HEK293/CHO
    HEK293 and CHO are mammalian expression systems. As a human cell line the HEK293 system provides the full range of post-translation modifications and proper folding so can be considered superior to other systems when producing human proteins.


    E.coli
    E.coli is the most common protein expression system. It offers the advantage of quick production and scale-up; however, proteins produced tend to have high endotoxin levels. Mammalian proteins produced using E.coli may not have the correct post-translational modifications and they often required refolding from solubilized inclusion bodies. This means that the functional activity of the protein is often inferior when compared to insect and mammalian expression systems.


    Yeast
    ​Yeast offers similar advantages to E.coli, ie quick production, but also offers eukaryotic post-translation modifications.


    Wheat germ
    Wheat germ is a cell-free protein expression system; however, proteins may lack correct folding and post-translation modifications.


    Baculovirus/Sf9/Sf21
    ​Baculovirus, Sf9 and Sf21 are insect expression systems. Insect systems provide the majority of post-translational modifications found in mammalian cells and facilitate proper protein folding.


    Protein tags
    Protein tags are peptide sequences included within the recombinant protein construct for solubilization and purification purposes. Tags can interfere with protein activity and should ideally be removed.

    All premium bioactive proteins are tag free. If a protein contains a tag, it will be listed near the bottom of the 'Description' section on its datasheet.


    Species
    ​There are many homologous proteins that perform the same function in different species. The level of similarity is determined by the degree of sequence homology. In many cases, bioactive proteins can be used across multiple species. However, they could show lower activity when compared to proteins for that specific species. For example, although a mouse cytokine could be active on human cells, a human cytokine would provide higher activity.



    Get resources and offers direct to your inbox Sign up
    A-Z by research area
    • Cancer
    • Cardiovascular
    • Cell biology
    • Developmental biology
    • Epigenetics & Nuclear signaling
    • Immunology
    • Metabolism
    • Microbiology
    • Neuroscience
    • Signal transduction
    • Stem cells
    A-Z by product type
    • Primary antibodies
    • Secondary antibodies
    • Biochemicals
    • Isotype controls
    • Flow cytometry multi-color selector
    • Kits
    • Loading controls
    • Lysates
    • Peptides
    • Proteins
    • Slides
    • Tags and cell markers
    • Tools & Reagents
    Help & support
    • Support
    • Make an Inquiry
    • Protocols & troubleshooting
    • Placing an order
    • RabMAb products
    • Biochemical product FAQs
    • Training
    • Browse by Target
    Company
    • Corporate site
    • Investor relations
    • Company news
    • Careers
    • About us
    • Blog
    Events
    • Tradeshows
    • Conferences
    International websites
    • abcam.cn
    • abcam.co.jp

    Join with us

    • LinkedIn
    • facebook
    • Twitter
    • YouTube
    • Terms of sale
    • Website terms of use
    • Cookie policy
    • Privacy policy
    • Legal
    • Modern slavery statement
    © 1998-2023 Abcam plc. All rights reserved.