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Recombinant Protein A

    產品資料評論相關產品實驗方法
     
    Quality Assurance
    Purity > 95% by SDS-PAGE Protein A
    Expression System: E coli.
    Molecular Mass: 34kD
    Form: Liquid or lyophilized
    Storage: -20℃ or below
    Concentration: Refer to the label on the vial
       
    Note: It is recommended that the protein be aliquoted and be used as soon as possible. Avoid repeated freeze-thaw cycles.
     
    Description
    Staphylococcal Protein A, or SPA, is a type I membrane protein covalently linked to the cell wall of most strains of the Gram-positive bacterium Staphylococcus aureus. It has high affinity to IgG from various species, for instance human, rabbit and guinea pig but only weak interaction with bovine and mouse. Protein A interacts with antibodies through two distinct binding events: the “classical” binding site on the Fc portion of human IgG1, IgG2, and IgG4, and the “alternate” binding site found on the Fab portion of human IgG, IgM, IgA, and IgE that contain heavy chains of the VH3 subfamily. The most reported molecular weight of protein A from Staphylococcus aureus is about 42,000. The recombinant Streptococci protein A consists of 299 amino acids and has a predicted molecular mass of 33.8 kDa as estimated by SDS-PAGE. antibody structure
    Protein A consists of three regions: S, being the signal sequence that is processed during secretion; five homologous IgG binding domains E, D, A, B and C and a cell-wall anchoring regionXM. The truncated protein lacking region X has a molecular weight of about 31kD. The domains are independently capable to bind to the Fc-part of IgG1, IgG2 and IgG4, but shows only weak interaction with IgG3. In addition, all native protein A domains show comparable Fab binding. The binding site for the Fc part of the IgG molecule has been determined in a study of the B domain. immunoglobulin binding domain
     
    Application

    The properties of protein A enables it as a powerful affinity ligand for several immunological and purification applications. High selectivity and good physiochemical stability have made protein A the preferred generic ligand for affinity purification of antibodies and molecules tagged with an antibody Fc-region. Protein A can also be used in various immunochemical assays including Western blotting, immunohistochemistry, and ELISA applications by conjugation with different reporter molecules, such as fluorescent dyes (FITC), enzyme markers (peroxidase, β-galactosidase, alkaline phosphatase), biotin, and colloidal gold. Immunoprecipitation studies with protein A conjugated to beads are also commonly used to purify proteins or protein complexes indirectly through antibodies against the protein or protein complex of interest.

     
    IgG binding of protein A, G, and L
     
    Species

    Protein A

    Protein G

    Protein L

     Human

     IgG

    +++

    +++

    +++

     

     IgG1

    ++++

    ++++

    ++++

     

     IgG2

    ++++

    ++++

    ++++

     

     IgG3

    -

    +++

    +++

     

     IgG4

    ++++

    ++++

    ++++

     

     IgA

    +

    -

    +++

     

     IgA1

    +

    -

    +++

     

     IgA2

    +

    -

    +++

     

     IgD

    -

    -

    +++

     

     IgE

    ++

    -

    +++

     

     IgM

    +

    -

    +++

     Rabbit

     IgG

    +++

    +++

    +

     Cow

     IgG

    +

    +++

    -

     

     IgG1

    +

    +++

    -

     

     IgG2

    +++

    +++

    -

     Cat

     IgG

    +++

    +

    ?

     Horse    

     IgG

    ++

    ++++

    ?

     Goat

     IgG

    +

    ++

    -

     

     IgG1

    +

    +++

    -

     

     IgG2

    +++

    +++

    -

     Guinea-pig

     IgG1

    ++

    +

    ?

     

     IgG2

    ++

    +

    ?

     Sheep

     IgG

    +

    ++

    -

     

     IgG1

    +

    ++

    -

     

     IgG2

    +++

    +++

    -

     Dog

     

    ++

    +

    ?

     Pig

     

    +++

    ++

    +++

     Rat

     IgG

    +

    ++

    +++

     

     IgG1

    -

    +

    +++

     

     IgG2a

    -

    ++++

    +++

     

     IgG2b

    -

    ++

    +++

     

     IgG2c

    ++

    ++

    +++

     

     IgG3

    +

    ++

    ?

     Mouse

     IgG

    ++

    ++

    +++

     

     IgG1

    +

    ++++

    +++

     

     IgG2a

    ++++

    ++++

    +++

     

     IgG2b

    +++

    +++

    +++

     

     IgG3

    ++

    +++

    +++

     

     IgM

    -

    -

    +++

     Chicken

     IgY

    -

    -

    -

     Monkey(rhesus)

     IgG

    ++++

    ++++

    ?

     Hamster

     

    +

    ++

    +++

     Koala

     

    -

    +

    ?

     Llama

     

    -

    +

    ?

     

    Strong binding ++, medium interaction +, weak or no interaction -.

     
    Related products
     
    Recombinant Protein G
    Recombinant Protein L
    rProtein A resin
    rProtein G resin
    rProtein L resin
     
     
    References
     
    1. Sanchayita Ghose, et al. (2007) Binding Capacity Differences for Antibodies and Fc-Fusion Proteins on Protein A Chromatographic Materials, Biotechnology and Bioengineering, Vol. 96, No. 4: 768-779
    2. Goding JW. (1978) Use of staphylococcal protein A as an immunological reagent. J Immunol Methods. 20: 241-53
    3. Sophia Hober, et al. (2007) Protein A chromatography for antibody purification, Journal of Chromatography B, 848: 40–47
    4. SVEN LÖFDAHL, et al. (1983) Gene for staphylococcal protein A, Proc. Nati Acad. Sci. USA, Vol 80: 697-701
    5. MATHIAS UHLEN, et al. (1984) Expression of the Gene Encoding Protein A in Staphylococcus aureus and Coagulase-Negative Staphylococci, JOURNAL OF BACTERIOLOGY, 713-719
    6. Tomas MOKS, et al. (1986) Staphylococcal protein A consists of five IgG-binding domains, Eur. J. Biochem., 156: 637-643
    7. Birger Jansson, et al. (1998) All individual domains of staphylococcal protein A show Fab binding, FEMS Immunology and Medical Microbiology, 20: 69-78
    8. MELISSA A. STAROVASNIK, et al. (1999) Antibody variable region binding by Staphylococcal protein A: Thermodynamic analysis and location of the Fv binding site on E-domain, Protein Science, 8: 1423–1431.
    9. http://en.wikipedia.org/wiki/Protein_A
     
     
    Size / Price
    貨號: 10600-P07E-10
    目錄價: 
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    Datasheet & Documentation

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