PydA is a Class III Extradiol ring-cleavage dioxygenase required for the degradation of 3-hydroxy-4-pyridone (HP).
This subfamily is composed of Rhizobium sp. PydA and similar proteins. PydA is required for the degradation of 3-hydroxy-4-pyridone (HP), an intermediate in the Leucaena toxin mimosine degradation pathway. It is a member of the class III extradiol dioxygenase family, a group of enzymes that use a non-heme Fe(II) to cleave aromatic rings between a hydroxylated carbon and an adjacent non-hydroxylated carbon. LigAB-like enzymes are usually composed of two subunits, designated A and B, which form a tetramer composed of two copies of each subunit. This model represents the catalytic subunit, B.