Ornithine decarboxylase (IPR002433)

Short name: Orn_de-COase

Overlapping homologous superfamilies

Family relationships


These enzymes are collectively known as group IV decarboxylases [PMID: 8181483]. Pyridoxal-dependent decarboxylases acting on ornithine, lysine, arginine and related substrates can be classified into two different families on the basis of sequence similarities [PMID: 3143046, PMID: 8181483]. Members of this family while most probably evolutionary related, do not share extensive regions of sequence similarities. The proteins contain a conserved lysine residue which is known, in mouse ODC [PMID: 1730582], to be the site of attachment of the pyridoxal-phosphate group. The proteins also contain a stretch of three consecutive glycine residues and has been proposed to be part of a substrate- binding region [PMID: 2198270].

The ornithine decarboxylases catalyse the transformation of ornithine into putrescine. Phylogenetic analysis of the mRNAs from several mammalian species suggests that ODC is encoded by orthologous genes in the different species. Analysis of divergence patterns in a number of subregions showed that the domains have evolved in a noncoordinate fashion. Evolution of each subregion has been episodic, with periods of both rapid and slow divergence, possibly indicating the existence of selection pressures that were exerted in a time- and domain-specific manner during mammalian speciation. The active form of mammalian ODC is a homodimer of 53 kDa subunits (the monomer retains no enzymatic activity). In vitro hybridisation and cross- linkage analysis have suggested that the active site of ODC is formed at the interface of the two monomers via the interaction of the cysteine-360- containing region of one subunit with the lysine-69-containing region of the other [PMID: 1730582].

This family also includes antizyme inhibitors (AZINs), which are ODC-homologous proteins lacking catalytic activity. They bind and inhibit the ODC antizyme [PMID: 8631929].

GO terms

Biological Process

GO:0006596 polyamine biosynthetic process

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.