| cation binding | GO:0043169 | 1.4 |
| oxygen transporter activity | GO:0005344 | 7.17 |
| substrate-specific transporter activity | GO:0022892 | 2.72 |
| transition metal ion binding | GO:0046914 | 2.48 |
| heme binding | GO:0020037 | 4.86 |
| tetrapyrrole binding | GO:0046906 | 4.8 |
| organic cyclic compound binding | GO:0097159 | 1.05 |
| ion binding | GO:0043167 | 1.36 |
| oxygen binding | GO:0019825 | 5.89 |
| binding | GO:0005488 | 0.18 |
| protein binding | GO:0005515 | 0.46 |
| transporter activity | GO:0005215 | 2.57 |
| iron ion binding | GO:0005506 | 4.65 |
| metal ion binding | GO:0046872 | 1.41 |
| heterocyclic compound binding | GO:1901363 | 1.06 |