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This report describes an ATP-diphosphohydrolase activity associated with the inner membrane of human term placental mitochondria. An enriched fraction containing 30 per cent of the total protein and 80 per cent of the total ATP-diphosphohydrolase activity was obtained from submitochondrial particles. ATP-diphosphohydrolase activity was characterized in this(More)
The kinetic characteristics of the transport of Ca2+ in the human term placental mitochondria previously depleted of their intramitochondrial calcium, was studied. Maximal Ca2+ uptake was observed in the presence of inorganic phosphate and ADP. Ca2+ transport showed a Michaelis-Menten behavior, with a Vmax of 61 nmol mg-1 min-1 and a Km of 118 microM.(More)
Alternative oxidase (AOX) is a ubiquitous respiratory enzyme found in plants, fungi, protists and some bacterial species. One of the major questions about this enzyme is related to its metabolic role(s) in cellular physiology, due to its capacity to bypass the proton-pumping cytochrome pathway, and as a consequence it has great energy-wasting potential. In(More)
INTRODUCTION Escherichia coli is recognized as an etiological bacteria associated with chorioamnionitis and the preterm premature rupture of fetal membranes. This pathological condition induces pro-inflammatory cytokines and degradative metalloproteinases, which are considered biological markers secreted in an acute stage of infection. Heat-shock proteins(More)
Mitochondrial thioredoxin-glutathione reductase was purified from larval Taenia crassiceps (cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At 25 degrees C specific activities were 437 +/- 27 mU mg(-1) and 840 +/- 49 mU mg(-1) with thioredoxin(More)
This study evaluated the effect of Ca2+ on the extramitochondrial hydrolysis of ATP and ADP by the extramitochondrial ATPase in isolated mitochondria and submitochondrial particles (SMPs) from human term placenta. The effect of different oxidizable substrates on the hydrolysis of ATP and ADP in the presence of sucrose or K+ was evaluated. Ca2+ increased(More)
Mitochondrial complexes I, III(2), and IV from human cytotrophoblast and syncytiotrophoblast associate to form supercomplexes or respirasomes, with the following stoichiometries: I(1):(III(2))(1) and I(1):(III(2))(1-2):IV(1-4). The content of respirasomes was similar in both cell types after isolating mitochondria. However, syncytiotrophoblast mitochondria(More)
Ustilago maydis is a fungal pathogen which is exposed during its life cycle to both abiotic and biotic stresses before and after the infection of maize. To cope with extreme environmental changes, microorganisms usually accumulate the disaccharide trehalose. We have investigated both the accumulation of trehalose and the activity of trehalase during the(More)
Rhizopus stolonifer (Ehrenb.:Fr.) Vuill mitochondria contain the complete system for oxidative phosphorylation, formed by the classical components of the electron transport chain (complexes I, II, III, and IV) and the F1F0-ATP synthase (complex V). Using the native gel electrophoresis, we have shown the existence of supramolecular associations of the(More)
The distribution of the alternative NADH dehydrogenase (NDH-2) in the living world was explored. The enzyme, although present in representatives of all living kingdoms, does not have a universal distribution. With the exception of ε-proteobacteria, the enzyme was found in all eubacterial groups. In contrast with the known presence of the NDH-2 in Archaea,(More)