Ornithine decarboxylase family. This family belongs to pyridoxal phosphate (PLP)-dependent aspartate aminotransferase superfamily (fold I). The major groups in this CD corresponds to ornithine decarboxylase (ODC), arginine decarboxylase (ADC) and lysine decarboxylase (LDC). ODC is a dodecamer composed of six homodimers and catalyzes the decarboxylation of tryptophan. ADC catalyzes the decarboxylation of arginine and LDC catalyzes the decarboxylation of lysine. Members of this family are widely found in all three forms of life.