The following Table compares the relative affinity of Protein A and Protein G for Mouse immunoglobulins (antibodies).
| Immunoglobulin type and class | Protein A binding | Protein G binding |
| IgG1 | + | +++ |
| IgG2a | +++ | +++ |
| IgG2b | ++ | ++ |
| IgG3 | ++ | +++ |
| IgM* | ++ | +/– |
| IgA | +++ | +++ |
