Dido Vassilacopoulou

Learn More
The Abeta peptide of Alzheimer disease is derived from the proteolytic processing of the amyloid precursor proteins (APP), which are considered type I transmembrane glycoproteins. Recently, however, soluble forms of full-length APP were also detected in several systems including chromaffin granules. In this report we used antisera specific for the(More)
The gene encoding BC200 RNA arose from a monomeric Alu element. Subsequently, the RNA had been recruited or exapted into a function of the nervous system. Here we confirm the presence of the BC200 gene in several primate species among the Anthropoidea. The period following the divergence of New World monkeys and Old World monkeys from their common ancestor(More)
We previously demonstrated the presence of a soluble form of full-length Alzheimer's amyloid precursor protein (APP) in the lumen of adrenal medullary chromaffin granules (CG). Furthermore, full-length APP is released from CG membranes in vitro at pH 9.0 by an enzymatic mechanism, sensitive to protease inhibitors [Vassilacopoulou et al. (1995) J. Neurochem.(More)
In the present study we demonstrate that enzymatically active l-Dopa decarboxylase (DDC) is expressed in U937 cells, an important model of human macrophage function. The mRNA coding for the enzyme was found to be of the neural-type. DDC was detected in both the soluble and membrane fractions. The active molecule is released from the membrane fraction in the(More)
Recent studies showed that the Alzheimer amyloid precursor (APP) occurs as the core protein of a chondroitin sulfate proteoglycan (appican) in C6 glioma cells. In the present study we show that appican is present in both human and rat brain tissue. Cortical rat brain cell cultures were used to identify appican-producing cells. Soluble secreted and(More)
L-Dopa decarboxylase (DDC) has been cloned from several species and was shown to undergo alternative splicing within its 5′-untranslated and coding regions. In this report we describe a novel splice variant of DDC mRNA in human tissue, lacking exons 10 - 15 of the full-length transcript but including an alternative exon 10. The isolated alternative human(More)
This work presents evidence on the association of active DDC molecules with membranes in mammalian brain. L-DOPA decarboxylase (DDC) is generally considered to be a cytosolic enzyme. Membrane-associated DDC was detected by immunoblotting and enzymatic assay experiments. DDC activity and immunoreactivity could be partially extracted from mammalian brain(More)
L-Dopa decarboxylase (DDC) is a pyridoxal 5-phosphate (PLP)-dependent enzyme that catalyses the decarboxylation of L-Dopa to dopamine. In this study we show the expression of DDC in human placental tissue and present data on the molecular cloning and in vitro expression of the active recombinant enzyme. Our analyses indicated the presence of both(More)
An endogenous inhibitor of l-Dopa decarboxylase was identified and purified from human serum. In Triton X-114 partitioning experiments, the inhibitor was recovered in the detergent enriched phase, suggesting a hydrophobic nature. Purification was achieved by means of proteinase K digestion, ammonium sulphate precipitation, phenyl sepharose hydrophobic(More)
An endogenous inhibitor of l-Dopa decarboxylase activity was identified and purified from human placenta. The endogenous inhibitor of l-Dopa decarboxylase (Ddc) was localized in the membrane fraction of placental tissue. Treatment of membranes with phosphatidylinositol-specific phospholipase C or proteinase K did not affect membrane-associated Ddc(More)