The following Table compares the relative affinity of Protein A and Protein G for Rat immunoglobulins (antibodies).
| Immunoglobulin type and class | Protein A | Protein G |
| IgG1 | – | + |
| IgG2a | – | +++ |
| IgG2 | – | ++ |
| IgG3 | + | ++ |
| IgM | – | – |
| – : No binding + : weak binding +++ : strong binding | ||
