Search results for "Enzyme complex"
showing 5 items of 55 documents
α-Synuclein expression levels do not significantly affect proteasome function and expression in mice and stably transfected PC12 cell lines
2004
α-Synuclein (α-syn) is a small protein of unknown function that is found aggregated in Lewy bodies, the histopathological hallmark of sporadic Parkinson disease and other synucleinopathies. Mutations in the α-syn gene and a triplication of its gene locus have been identified in early onset familial Parkinson disease. α-Syn turnover can be mediated by the proteasome pathway. A survey of published data may lead to the suggestion that overexpression of α-syn wild type, and/or their variants (A53T and A30P), may produce a decrease in proteasome activity and function, contributing to α-syn aggregation. To investigate the relationship between synuclein expression and proteasome function we have s…
Novel inhibitors of mitochondrial respiratory chain: endoperoxides from the marine tunicate Stolonica socialis.
2001
The Mediterranean tunicate Stolonica socialis contains a new class of powerful cytotoxic acetogenins, generically named stolonoxides. In this paper, which also details the isolation and chemical characterization of a minor component (3a) of the tunicate extract, we report the potent inhibitory activity (IC(50) < 1 microM) of stolonoxides (1a and 3a) on mitochondrial electron transfer. The compounds affect specifically the functionality of complex II (succinate:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome C oxidoreductase) in mammalian cells, thereby causing a rapid collapse of the whole energetic metabolism. This result, which differs from the properties of similar known…
New molecular aspects of regulation of mitochondrial activity by fenofibrate and fasting
2000
Abstract Fenofibrate and fasting are known to regulate several genes involved in lipid metabolism in a similar way. In this study measuring several mitochondrial enzyme activities, we demonstrate that, in contrast to citrate synthase and complex II, cytochrome c oxidase (COX) is a specific target of these two treatments. In mouse liver organelles, Western blot experiments indicated that mitochondrial levels of p43, a mitochondrial T3 receptor, and mitochondrial peroxisome proliferator activated receptor (mt-PPAR), previously described as a dimeric partner of p43 in the organelle, are increased by both fenofibrate and fasting. In addition, in PPARα-deficient mice, this influence was abolishe…
Engineering a Saccharomyces cerevisiae Wine Yeast That Exhibits Reduced Ethanol Production during Fermentation under Controlled Microoxygenation Cond…
2006
ABSTRACTWe recently showed that expressing an H2O-NADH oxidase inSaccharomyces cerevisiaedrastically reduces the intracellular NADH concentration and substantially alters the distribution of metabolic fluxes in the cell. Although the engineered strain produces a reduced amount of ethanol, a high level of acetaldehyde accumulates early in the process (1 g/liter), impairing growth and fermentation performance. To overcome these undesirable effects, we carried out a comprehensive analysis of the impact of oxygen on the metabolic network of the same NADH oxidase-expressing strain. While reducing the oxygen transfer rate led to a gradual recovery of the growth and fermentation performance, its i…
Inhibition of the herpes simplex virus-coded thymidine kinase-complex by 9-?-D-arabinofuranosyladenine 5?-monophosphate (ara-AMP) and 9-(2-hydroxyeth…
1984
The thymidine kinase-complex isolated from herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) is associated with the following enzyme activities: ATP:dThd (dCyd) deoxypyrimidine kinase, ATP:dTMP thymidylate kinase, ADP:dThd- and AMP:dThd5′-phosphotransferase. In kinetic experiments it is shown that ara-AMP inhibits AMP:dThd- and ADP:dThd phosphotransferase activity, while acyclo-GMP impairs ADP:dThd phosphotransferase reaction only; the inhibition was found to be non-compertitive. The functional subunit ATP:dThd kinase was not affected by either compound.