Are you still using Sepharose®/Agarose slurry?

• Dynabeads® Protein A and Protein G are the new gold standard for immunoprecipitation.
  
  Magnetic handling is fast, efficient and extremely gentle on your target proteins. All steps take place in a single tube, with no centrifugations. Bound only by affinity interactions, your protein and protein complexes are preserved intact. Your immunoprecipitation is ensured maximum sensitivity and no loss of target protein.
  
  Bring your research tools up to date now!
  
  Sepharose® is a trademark of GE Healthcare companies.

• Why not get it all !   With Dynabeads® Protein A and Dynabeads® Protein G.
  Take advantage of this introductory offer now!
  (offer valid in Europe, US, Canada, Australia, New Zealand and Singapore)

Other Product Advantages for Dynabeads® Protein A and Protein G:

• • Perfect for small-scale IgG purification and immunoprecipitation
  • No columns, centrifugations, or time-consuming pre-treatment of your samples
  • Easy handling and simple protocol (workflow)
  • Gentle, minimal physical stress on precious proteins
  • Starting sample can be saliva, plasma, ascites, serum, and tissue culture or hybridoma supernatants
  • The recombinant protein A/G on the beads contains no albumin binding sites, thus avoiding co-purification of contaminating proteins

Shorter protocol time. Better yield and reproducibility with Dynabeads Immunoprecipitation Kit

Which suits your research best: Protein A or Protein G?

• Native protein G and protein A differ in their binding strength to mmunoglobulins (Ig) from different species and subclasses. (As an example, human IgG3 will bind strongly to protein G, but only weakly to protein A.) The table below gives an overview of binding strengths of protein G and protein A to different Ig species and subclasses. 
  +++: strong binding, ++: medium binding, +: weak binding, -: no binding.
  
  

  Species	Ig Subclass	Protein A	Protein G
  Human	Total Ig IgG1, IgG2, IgG4 IgG3 IgD IgD Fab ScFv	+++ +++ + - + + +	+++ +++ +++ - - + -
  Mouse	Total Ig IgG1 IgG2a, IgG2b, IgG3 IgM	+++ + +++ -	+++ ++ +++ -
  Rat	Total Ig IgG1  IgG2a IgG2b IgG2c	+ + - - +++	++ ++ +++ + +++
  Goat	Total Ig IgG1 IgG2	+ + +++	+++ +++ +++
  Sheep	Total Ig IgG1 IgG2	+ + +++	+++ +++ +++
  Cow / Bovine	Total Ig IgG1 IgG2	+ + +++	+++ +++ +++
  Horse	Total Ig IgG(ab) IgG(c) IgG(T)	+ + + -	+++ - - +++
  Rabbit	Total Ig	+++	+++
  Dog	Total Ig	+++	+
  Cat	Total Ig	+++	+
  Pig	Total Ig	+++	+
  Guinea pig	Total Ig	+++	+
  Chicken	Total Ig	-	-

  
  For other Igs or isolation techniques, check the selection guide for our full range of Dynabeads® for immunoprecipitation.

More information about Immunoprecipitation:

• Binding of antibodies to the beads in solution is an equilibrium reaction. To capture as many antibodies as possible, be aware of the following: The reaction volume should be kept low to maintain high concentrations of beads and antibody. There is no need for pre-treating the samples (even viscous samples), so no dilutions of sample or beads should be done. If the antibody concentration in the sample is suspected to be very low, the amount of beads can be increased.
  
  Instead of eluting off the antibody, the Dynabeads® may be resuspended in a Na-phosphate buffer (Figure 2). The bead-bound antibody can be used for immunoprecipitation of specific proteins in any type of sample. To prevent co-elution of the antibody, it is possible to cross-link the antibody to protein A/G prior to the immunoprecipitation steps. This is not necessary for downstream SDS-PAGE followed by autoradiography or western blotting, and optional for Silver or Coomassie® staining.
  
  

  Figure 2 - Different elution properties for captured proteins

  Figure 1 - Affinity purification of human IgG and immunoprecipitation of human serum albumin from 2 µl serum, using Dynabeads® Protein A. Lane 1 - Purified IgG from serum. Lane 2: Immunoprecipitated human serum albumin (cross-linking omitted thus antibody present). Lane 3: 50 x diluted serum. Lane 4: LMW.

Table 1 - Properties of the recombinant Protein A and Protein G in Dynabeads®

• Dynabeads® Protein A and  Dynabeads® Protein G bind with different affinities depending on the immunoglobulin type and species. Binding occurs mainly through the Fc region. The binding capacity will depend on the initial concentration of antibodies in the sample and the source of the antibody. These data are based on isolation from a sample containing 100 µg immunoglobulin per ml.
  
  

  	Protein A	Protein G
  Source	Bacillus	E.coli
  Molecular weight	45 kDa	17 kDa
  No.of binding sites for IgG	4	2
  Binding capacity*	250 µg human IgG / ml beads	640 µg mouse IgG / ml beads
  Optimal binding pH	8.2	7.0