Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated a simplified method for preparation and analysis of platelet cytochrome c oxidase activity in Alzheimer's disease (AD) and control patients. Mean cytochrome c oxidase activity in controls (n = 17) was 0.233 sec-1/mg whereas mean cytochrome c oxidase activity in Alzheimer patients (n = 19) was 0.193 sec-1/mg, p = 0.033. Complex III (ubiquinol:cytochrome c oxidoreductase), complex II (succinic dehydrogenase), and citrate synthase were all assayed as internal controls and were not significantly different in controls and Alzheimer patients. There is a relatively specific loss of platelet cytochrome c oxidase activity in Alzheimer disease patients.
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PMID:Reduced platelet cytochrome c oxidase activity in Alzheimer's disease. 761 12

Defects in mitochondrial oxidative metabolism, in particular decreased activity of cytochrome c oxidase, have been demonstrated in Alzheimer's disease, and after the expression of the amyloid precursor protein (APP) in cultured cells, suggesting that mitochondria might be involved in beta-amyloid toxicity. Recent evidence suggests that the proteolysis of APP to generate beta-amyloid is at least in part intracellular, preceding the deposition of extracellular fibrils. We have therefore investigated the effect of incubation of isolated rat brain mitochondria with the beta-amyloid fragment 25-35 (100 microM) on the activities of the mitochondrial respiratory chain complexes I, II-III, IV (cytochrome c oxidase) and citrate synthase. The peptide caused a rapid, dose-dependent decrease in the activity of complex IV, white it had no effect on the activities on any of the other enzymes tested. The reverse sequence peptide (35-25) had no effect on any of the activities measured. We conclude that inhibition of mitochondrial complex IV might be a contributing factor to the pathogenesis of Alzheimer's disease.
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PMID:beta-Amyloid fragment 25-35 selectively decreases complex IV activity in isolated mitochondria. 1048 79

It has been suggested that the lateralization of the human brain underlies hemispheric specialization and that it can be observed also on a biochemical level. Biochemical laterality appears to be a basis of volumetric or functional asymmetry but direct relationships among them are still unclear. Moreover, age-related differences between the right and left hemispheres are not well documented in various rat strains. In the current study, biochemical markers sensitive to Alzheimer disease (activities of high-affinity choline uptake and of nitric oxide synthases, expression of 17beta-hydroxysteroid dehydrogenase type 10) were estimated in both hemispheres of young and old male Wistar/Long Evans rats. Our experiments indicate (1) differences in some biochemical markers between young Wistar and Long Evans rats (the activities of endothelial nitric oxide synthase are higher in Long Evans and those of citrate synthase in Wistar rats), (2) more similar brain asymmetry of healthy human/young Wistar brains when compared to those of young Long Evans, (3) the decrease in asymmetry of the physiologically left/right lateralized biomarker during aging (the activity of the high-affinity choline uptake decreases more markedly in the left side of old Wistar rats) in accordance with the HAROLD model, (4) the age-related shift to reversed left/right asymmetry of the physiologically right/left lateralized biomarker (the activity of inducible nitric oxide synthase increases especially in the left side of old Long Evans rats), and finally (5) age-related differences in physiologically unlateralized biomarkers between Wistar and Long Evans rats (changes in the activities of neural/endothelial nitric oxide synthases or in expression of 17beta-hydroxysteroid dehydrogenase type 10 are more asymmetrical in old Wistar when compared to rather bilateral alterations of old Long Evans animals). It seems that the physiological lateralization of the human or rat brains on a biochemical level and their age-related alterations are dependent on biomarker type/function. By our opinion, it is difficult, perhaps impossible, to make one simple universal model, at least on a biochemical level. Since lateral analyses are of sufficient sensitivity to reveal subtle links, we recommend using Wistar rather than Long Evans rats in modeling of diseases accompanied by alterations in brain asymmetry.
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PMID:Aging and lateralization of the rat brain on a biochemical level. 2036 89

Primary aerial surfaces of land plants are coated by a lipidic cuticle, which forms a barrier against transpirational water loss and protects the plant from diverse stresses. Four enzymes of a fatty acid elongase complex are required for the synthesis of very-long-chain fatty acid (VLCFA) precursors of cuticular waxes. Fatty acid elongase substrate specificity is determined by a condensing enzyme that catalyzes the first reaction carried out by the complex. In Arabidopsis (Arabidopsis thaliana), characterized condensing enzymes involved in wax synthesis can only elongate VLCFAs up to 28 carbons (C28) in length, despite the predominance of C29 to C31 monomers in Arabidopsis stem wax. This suggests additional proteins are required for elongation beyond C28. The wax-deficient mutant eceriferum2 (cer2) lacks waxes longer than C28, implying that CER2, a putative BAHD acyltransferase, is required for C28 elongation. Here, we characterize the cer2 mutant and demonstrate that green fluorescent protein-tagged CER2 localizes to the endoplasmic reticulum, the site of VLCFA biosynthesis. We use site-directed mutagenesis to show that the classification of CER2 as a BAHD acyltransferase based on sequence homology does not fit with CER2 catalytic activity. Finally, we provide evidence for the function of CER2 in C28 elongation by an assay in yeast (Saccharomyces cerevisiae).
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PMID:Arabidopsis ECERIFERUM2 is a component of the fatty acid elongation machinery required for fatty acid extension to exceptional lengths. 2293 Jul 48