Summary for clan CQ
| Description | Cysteine nucleophile; catalytic residues in the order Glu, His, Cys in sequence | ||
Families
| Family | Family Type Peptidase | Structure |
| C53 | pestivirus Npro peptidase (classical swine fever virus) | Yes |
Distribution of clan CQ among Kingdoms of Organisms
| Family | Bacteria | Archaea | Protozoa | Fungi | Plants | Animals | Viruses |
| C53 | - | - | - | - | - | + | + |
| Clan | - | - | - | - | - | + | + |
