title: Use of radiolabeled monofluoromethyl-Dopa to define the subunit structure of human L-Dopa decarboxylase.
abstract: Human L-Dopa decarboxylase (L-aromatic amino acid decarboxylase, DDC) has been purified from pheochromocytoma tissue, a benign tumor of the catecholamine-synthesizing cells of the adrenal medulla. The binding characteristics of a new radiolabeled enzyme-activated suicide inhibitor of DDC ( [3H]monofluoromethyl-Dopa, [3H]MFMD) have been established, and the covalent linkage of the inhibitor to the enzyme has been used to identify that human DDC exists as a dimer of a 50-kDa subunit. An antibody to human DDC identically precipitates the enzyme activity from different human, rat, and mouse tissues. Our data demonstrate the value of [3H]MFMD for probing the structure of DDC and facilitating the purification of this enzyme, and further emphasize the high degree of conservation of the DDC molecule over a wide variety of species.
mesh_terms: D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004296:Dopa Decarboxylase / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008750:Methyldopa / Q000031:analogs & derivatives* / Q000494:pharmacology; D051379:Mice; D011487:Protein Conformation; D051381:Rats; D013045:Species Specificity; D014018:Tissue Distribution
chemical_list: D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D008750:Methyldopa; C019494:alpha-monofluoromethyldopa; D004296:Dopa Decarboxylase; D001142:Aromatic-L-Amino-Acid Decarboxylases