Specification :

Source: E.coli;
M.W.: Protein A is a cell wall component produced by several strains of Staphylococcus aureus that consists of a single polypeptide chain and contains little or no carbohydrate. Recombinant Protein A is produced in E.Coli and functions essentially the same as native Protein A. It consists of 5 IgG-binding domains E-D-A-B-C aligned in series. It migrates with an apparent molecular mass of 45 kDa in SDS-PAGE;
Purity: >95% by SDS-PAGE analyses;
Endotoxin Level: Less than 1 EU/ug of Protein A as determined by LAL method;
A280 of 0.1% solution ¡«0.165
Formulation: Lyophilized with no additive;
Specificity: The interaction between Protein A and IgG is not equivalent for all species. Even within a species, Protein A interacts with some subclasses of IgG and not others. For instance, human IgG1, IgG2 and IgG4 bind strongly, while IgG3 does not bind. There are also many instances in which monoclonal antibodies do not bind to Protein A, especially the majority of rat immunoglobulins and mouse IgG1;
Applications: The Protein A molecule contains four high affinity (Ka = 108 /mole) binding sites capable of interacting with the Fc region from IgG of several species including human and rabbit. Optimal binding occurs a pH 8.2, although binding is also good at neutral or physiological conditions (pH 7.0-7.6);