Victoria E. Espinosa

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Apyrase/ATP-diphosphohydrolase hydrolyzes di- and triphosphorylated nucleosides in the presence of a bivalent ion with sequential release of orthophosphate. We performed studies of substrate specificity on homogeneous isoapyrases from two potato tuber clonal varieties: Desiree (low ATPase/ADPase ratio) and Pimpernel (high ATPase/ADPase ratio) by measuring(More)
Arsenic has been associated with multiple harmful effects at the cellular level. Indirectly these defects could be related to impairment of the integrity of the immune system, in particular in lymphoid population. To characterize the effect of Arsenic on redox status on this population, copper smelter workers and arsenic unexposed donors were recruited for(More)
Continuing our search to find more potent and selective 5-LOX inhibitors, we present now the enzymatic evaluation of seventeen isoflavones (IR) and nine isoflavans (HIR), and their in vitro and in cellulo potency against human leukocyte 5-LOX. Of the 26 compounds tested, 10 isoflavones and 9 isoflavans possessed micromolar potency, but only three were(More)
Comparative studies of intrinsic and extrinsic fluorescence of apyrases purified from two potato tuber varieties (Pimpernel and Desirée) were performed to determine differences in the microenvironment of the nucleotide binding site. The dissociation constants (K(d)) of Pimpernel apyrase for the binding of different fluorescent substrate analogs:(More)
ATP-diphosphohydrolase (apyrase. EC 3.6.1.5) has both ATPase and ADPase activity that are stimulated by bivalent metals, with Ca2+ being the most effective. The possible physiological function of this enzyme, associated with placental and renal microvilli, is related to the extracellular metabolism of nucleotides. A comparison of the biochemical properties(More)
Extracellular nucleotides interact with specific receptors on the cell surface and are locally metabolized by ecto-nucleotidases. Biochemical characterization of the ATPase and ADPase activities detected in rat heart sarcolemma, under conditions where mitochondrial ATPase and adenylate kinase were blocked, supports our proposal that both activities(More)
In this study, we have investigated 16 isoflavone and isoflavan derivatives as potential inhibitors of human lipoxygenase (platelet 12-lipoxygenase, reticulocyte 15-lipoxygenase-1, and epithelial 15-lipoxygenase-2). The flavonoid baicalein, a known lipoxygenase inhibitor, was used as positive control. Four compounds, 6,7-dihydroxy-3'-chloroisoflavone (1c),(More)
Propolis and grape pomace have significant amounts of phenols which can take part in anti-inflammatory mechanisms. As the cyclooxygenases 1 and 2 (COX-1 and COX-2) are involved in said mechanisms, the possibility for a selective inhibition of COX-2 was analyzed in vitro and in silico. Propolis and grape pomace from Uruguayan species were collected,(More)
A set of aryloxy-quinones, previously synthesized and evaluated against Trypanosoma cruzi epimastigotes cultures, were found more potent and selective than nifurtimox. One of the possible mechanisms of the trypanocidal activity of these quinones could be inhibition of trypanothione reductase (TR). Considering that glutathione reductase (GR) is the(More)