InterPro: IPR002985 Arginine decarboxylase

Pyridoxal-dependent decarboxylases that act on ornithine-, lysine-, arginine- and related substrates can be classified into different families on the basis of sequence similarity [1, 2]. One of these families includes eukaryotic ornithine decarboxylase (ODC), which catalyses the transformation of ornithine into putrescine; prokaryotic diaminopimelic acid decarboxylase (DAPDC), which catalyses the conversion of diaminopimelic acid into lysine, the final step of lysine biosynthesis; Pseudomonas syringae pv. tabaci protein, tabA, which is probably involved in tabtoxin biosynthesis and is similar to DAPDC; and bacterial and plant biosynthetic arginine decarboxylase (ADC), which catalyses the transformation of arginine into agmatine, the first step in putrescine synthesis from arginine.

Although these proteins, which are known collectively as group IV decarboxylases [2], probably share a common evolutionary origin, their levels of sequence similarity are low, being confined to a few short conserved regions. The tomato ADC gene contains an open reading frame encoding a polypeptide of 502 amino acids and a predicted molecular mass of ~55kDa [3]. The predicted amino acid sequence shares 47 and 38% identify with oat and Escherichia coli ADCs, respectively. Gel blot hybridisation experiments show that, in tomato, ADC is encoded by a single gene and is expressed as a transcript of ~2.2 kb in the fruit pericarp and leaf tissues [3].