The active form of ornithine decarboxylase is a homodimer.
Each monomer contains a barrel domain, consisting of an alpha-beta barrel, and a sheet domain, composed of two beta-sheets.
The domains are connected by loops.
The monomers connect to each other via interactions between the barrel of one monomer and the sheet of the other.
Binding between monomers is relatively weak, and ODC interconverts rapidly between monomeric and dimeric forms in the cell.

The pyridoxal phosphate cofactor binds lysine 69 at the C-terminus end of the barrel domain.
 The active site is at the interface of the two domains, in a cavity formed by loops from both monomers.
The active form of ornithine decarboxylase is a homodimer. Each monomer contains a barrel domain, consisting of an alpha-beta barrel, and a sheet domain, composed of two beta-sheets. The domains are connected by loops. The monomers connect to each other via interactions between the barrel of one monomer and the sheet of the other. Binding between monomers is relatively weak, and ODC interconverts rapidly between monomeric and dimeric forms in the cell.
The pyridoxal phosphate cofactor binds lysine 69 at the C-terminus end of the barrel domain.  The active site is at the interface of the two domains, in a cavity formed by loops from both monomers.
Ornithine decarboxylase