Recombinant Protein A

Cat: 10600-P07E

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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

Other Proteins

The influence of pH on the binding of immunoglobulin G to staphylococcal protein A

Author:
Plummer, BT;
Year:
2013
Journal:
Thesis
Application:
binding
 

Generation and tumor recognition properties of two human monoclonal antibodies specific to cell surface anionic phospholipids

Author:
Bujak, E;Pretto, F;Neri, D;
Year:
2015
Journal:
Invest New Drugs
Application:
binding

PubMed ID: 25983040

 

Low dose of protein A pretreatment can alleviate the inflammatory reaction and the bio-safety was evaluated in vivo

Author:
Wang, D;Liu, Y;Zhao, Y;Zhou, J;
Year:
2016
Journal:
J Chin Med Assoc
Application:
animal-based
 

Efficient Generation of Bispecific Murine Antibodies for Pre-Clinical Investigations in Syngeneic Rodent Models

Author:
Labrijn, AF;Meesters, JI;Bunce, M;Armstrong, AA;Somani, S;Nesspor, TC;Chiu, ML;Altintaş, I;Verploegen, S;Schuurman, J;Parren, PWHI;
Year:
2017
Journal:
Sci Rep
Application:
purification

PubMed ID: 28559564

 
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