| Feature | BINDING |
| Definition | Binding site for any chemical group (co-enzyme, prosthetic group, etc.). The chemical nature of the group is indicated in the NOTE qualifier |
| Optional Qualifiers | /NOTE="free text" |
| Comment | Examples of values for the "NOTE" qualifier: 'Heme (covalent)' and 'Chloride'. Where appropriate, the features keys CA_BIND, DNA_BIND, METAL,and NP_BIND should be used rather than BINDING. |