GenScript Protein G Resin FF is an affinity chromatography medium designed for easy, one-step purification of classes, subclasses and fragments of immunoglobulins from biological fluids and from cell culture media. The recombinant protein G ligand is coupled to 4% highly cross-linked agarose. The static binding capacity of Protein G Resin FF is greater than 20 mg human IgG/ml settled resin. The dynamic binding capacity will vary depending on several factors such as target antibody, flow rate etc. Table 1 lists the characteristics of Protein G Resin FF.
Protein G, a bacterial cell wall protein isolated from group G Streptococci, binds to mammalian IgGs mainly through Fc regions. Native protein G has 3 IgG binding domains and also sites for albumin and cell-surface binding. The latter have been eliminated from recombinant protein G to reduce nonspecific binding. Although protein G has very similar tertiary structures to protein A, their amino acid compositions differ significantly, resulting in different binding characteristics. Protein G can be used for purification of mammalian monoclonal and polyclonal IgGs that do not bind well to protein A. Protein G has greater affinity than protein A for most mammalian IgGs, especially for certain subclasses including human IgG3, mouse IgG1 and rat IgG2a. Unlike protein A, protein G does not bind to human IgM, IgD and IgA.
Storage
Store in 20% ethanol at 2°C to 8°C. Do not freeze.
Characteristics
| Ligand | Recombinant Streptococcal protein G lacking the albumin-binding sites expressed in E. coli |
| Number of IgG binding sites per ligand | 3 |
| M.W. of ligand | Approximately 22 kDa |
| PI of ligand | 4.69 |
| Degree of substitution | Approximately 2 mg protein G/ml settled resin |
| Static binding capacity | ≥ 20 mg human IgG/ml settled resin |
| Matrix spherical | 4% highly cross-linked agarose |
| Average particle size | 90 μm (45-165 μm) |
| Recommended flow rate | 50-300cm/h |
| Storage solution | 20% ethanol |
| Storage and Stability | 18 months when stored unopened at 2-8 °C |