Protein G Coated Surfaces

The Biomat product is a 96 well coated microplate with recombinant Proein G and a protein to block non-specific binding sites and to maintain stable activity.

Protein G specifically binds the Fc region of immunoglobulins of many mammalian species ( see table 1 ), with an orientation that allows the F(ab)2 binding sites to be freely available for efficient binding to epitope. When coated onto microplates, the Protein G can securely capture IgG applied directly or as antigen/antibody complexes.

Example of applications:

Product specifications

Components
Individually pouched 96-well microplates, configured in 12 removable 8-well strips

Coating
Recombinant Protein G ( mol. weight 26.1 kDa ) ,from Streptococcus sp., expressed in E.coli, is coated using 100 μl/well. The strips are post-coated ( blocked ) for low non specific binding and long-term stability.

Binding capacity
Microplate was saturated with human IgG at a concentration of 8.0 μg/ml ( 800 ng/well ) in an ELISA format using Streptavidin-HRP as detector and TMB as substrate ( see Figure 1 for data and experiment details ).
The Biomat Protein G microplate shows a nominal binding capacity of ~ 5.3 pmol IgG/well

Sensitivity
Biotinylated human IgG was detected at a concentration significantly above background in an ELISA format using streptavidin-HRP as detector and TMB as substrate ( see Figure 2 for data and experiment details ).
The Biomat Protein G microplate shows a sensitivity of 0.056 ng/well of human IgG.

Uniformity
Microplates show a CV% less than 5 when used as a catcher of biotinylated human IgG in an ELISA format using streptavidin-HRP as detector and TMB as substrate.

Storage and Stability
The microplates, if unopened, are stable refrigerated until the expiration date printed on the label. If opened,store in closed pouch with dessicant and use within the expiration date.

Table 1. Binding affinities of recombinant Protein A and G for Immunoglobulin binding domains

(The table below gives an overview of binding strengths of protein A and G to different species and subclasses. S : strong binding;M : medium binding; W: weak binding; N : no binding)

Species Ig Subclass Protein A Protein G
Human Total Ig S S
IgG1,IgG2,IgG4 S S
IgG3 W S
IgD W N
IgA W N
IgE W N
IgM W N
Mouse Total Ig S S
IgG1 W M
IgG2a, IgG2b,IgG3 S S
IgM N N
Rabbit IgG S S
Rat IgG N W-S
Goat IgG W-M M-S
Sheep IgG W-M M-S
Chicken IgG N W
Guinea Pig IgG S W-M
Hamster IgG W M
Horse IgG W S
Pig IgG S W-M
Bovine IgG M S
Dog IgG S W-M
Cat IgG S W