Pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase. Primary structure and relationships to other amino acid decarboxylases

The complete amino acid sequence of pig kidney 3,4-dihydroxyphenylalanine (Dopa) decarboxylase is reported. The sequence was determined from analysis of peptides isolated after tryptic and cyanogen bromide cleavages of the enzyme. Each subunit is made up of 485 residues, corresponding to a molecular mass of 53858 Da. The N-terminus of the polypeptide chain is an acetylated methionyl residue. A number of structural features, previously shown to be important for the structure and function of the enzyme, could be localized along the polypeptide chain. Comparison of the primary structure with the known cDNA-deduced sequences of other Dopa decarboxylases (i.e. the human, bovine, rat, guinea-pig and Drosophila enzymes) reveals 50% identity. The identity increases to 73%, if the comparison is restricted to the mammalian sequences. Comparison with other aromatic and non-aromatic decarboxylases allows some consideration to be made in terms of structure/function and evolutionary relationships in this class of enzymes.