title: Release of membrane-associated L-dopa decarboxylase from human cells.
abstract: L-Dopa Decarboxylase is a pyridoxal 5-phosphate (PLP)-dependent enzyme that catalyses the decarboxylation of L-Dopa to dopamine. In this study, we investigated the cellular topology of the active human enzyme. Fractionation of membranes from human cell lines, of neural and non-neural origin, by temperature-induced phase separation in Triton X-114 resulted in the detection of DDC molecules in all separation phases. Solubilization of membrane-associated DDC was observed in a pH and time-dependent manner and was affected by divalent cations and protease inhibitors, suggesting the involvement of a possible release mechanism. The study of the biological properties and function of the solubilization phenomenon described here, as well as, the study of the membrane-associated enzyme could provide us with new information about the participation of the human L-Dopa decarboxylase in physiological and aberrant processes.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Athens, Panepistimiopolis, Zografou, 15701, Athens, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Chalatsa
authors.forename: Emmanuel G
authors.initials: EG
authors.lastname: Fragoulis
authors.forename: Dido
authors.initials: D
authors.lastname: Vassilacopoulou
mesh_terms: D002412:Cations / Q000737:chemistry; D002458:Cell Fractionation; D002460:Cell Line; D003902:Detergents / Q000737:chemistry; D004296:Dopa Decarboxylase / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008566:Membranes / Q000737:chemistry / Q000201:enzymology*; D008670:Metals / Q000737:chemistry; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism
chemical_list: D002412:Cations; D003902:Detergents; D008670:Metals; D011480:Protease Inhibitors; D004296:Dopa Decarboxylase