Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male Wistar rats administered repetitively with pentylenetetrazol developed a dose-dependent enhancement of seizure behaviour referred to as pentylenetetrazol kindling. After a daily dose of 40 mg pentylenetetrazol/kg or physiological saline (control rats) injected intraperitoneally for a period of two weeks, hippocampal tissue was studied autoradiographically for high-affinity uptake of [3H]glutamate and, by activity staining, for aspartate aminotransferase and glutamate dehydrogenase. Most prominent changes were found in neuropil areas known to be endowed with glutamatergic structures. The uptake capacity of glutamate decreased by 48% (maximum rate), whilst activities of aspartate aminotransferase and glutamate dehydrogenase elevated to 140 and 130%, respectively. Cytochrome c oxidase activity was found to be unaffected. The findings indicate an important role of factors of the glutamate metabolism in the kindling process with respect to the production, utilization, and availability of transmitter glutamate.
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PMID:Pentylenetetrazol kindling and factors of glutamate transmitter metabolism in rat hippocampus. 135 55

It has been reported that the mitochondrial cytochromes and citrate cycle enzymes occur in constant proportions to each other and increase or decrease roughly in parallel in response to various stimuli. The purpose of this study was to determine whether this proportionality is an obligatory consequence of the way in which mitochondria are assembled. Severe iron deficiency was used to bring about decreases of the iron-containing constituents of the mitochondrial respiratory chain in skeletal muscle. Cytochrome c concentration and cytochrome oxidase activity were decreased approximately 50%, while succinate dehydrogenase and NADH dehydrogenase activities were decreased by 78% in iron-deficient muscle. On electron microscopic examination, mitochondria in iron-deficient muscles had relatively sparse numbers of cristae. The iron deficiency had little or no effect on the levels of a range of mitochondrial matrix enzymes, including citrate synthase, isocitrate dehydrogenase, fumarase, aspartate aminotransferase, 3-hydroxyacyl-CoA dehydrogenase, 3-ketoacid-CoA transferase, and acetoacetyl-CoA thiolase. These results show that the usual constant proportions between the constituents of the mitochondrial respiratory chain and matrix enzymes are not obligatory; they provide evidence that mitochondrial matrix enzymes and respiratory chain constituents can be incorporated into mitochondria independently and that the ratios between them can vary within wide limits.
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PMID:Perturbation of mitochondrial composition in muscle by iron deficiency. Implications regarding regulation of mitochondrial assembly. 302 53

1) The oxygen consumption increases during Bufo bufo development in accordance with the two steps which border at the "heart beat" stage. 2) Cytochrome c oxidase activity is not proportional to the oxygen consumption: it is notable and constant in the first step, and it only increases in the second. 3) In the mitochondria of preneural embryos, citrate synthase, NADP+ dependent isocitrate dehydrogenase, and succinate dehydrogenase activities are very low in respect to malate dehydrogenase and glutamate oxaloacetate transaminase activities. The Krebs cycle results lowered at the condensing reaction level with acetyl accumulation when pyruvate is available. The same behavior has been observed in the Xenopus laevis oocytes and differentiated tissues. 4) The presence of a phosphagen system which is different from creatine phosphate and arginine phosphate, supporting ATP level, has been demonstrated in B. bufo embryos. 5) Mitochondria of postneural embryos are able to accomplish a complete Krebs cycle by increasing citrate synthase, and succinate dehydrogenase activities. 6) In all B. bufo development, malate dehydrogenase and glutamate oxaloacetate transaminase constitute a multienzymatic system by which the mitochondria accomplish a decarboxylic amino acid shunt required for the transformation of deutoplasm into protoplasm. This shunt is also operative in the X. laevis oocytes. 7) Through pyruvate production, by oxidative decarboxylation of malate, the NAD(P)+ dependent malic enzyme could carry out a fundamental anaplerotic function in the mitochondria which is specialized in the production of biosynthetic blocks belonging to the embryo in which the carbohydrates metabolism rather than the glycolytic activity is designed for pentose phosphate and glycerol phosphate synthesis for protein and cytomembrane production. 8) Consistent metabolic differences have been highlighted between B. bufo embryos and X. laevis embryos.
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PMID:Physiological differentiation of the mitochondria during Bufo bufo development. 1125 8

Mitochondrial aspartate aminotransferase (mAspAT) (E.C. 2.6.1.1), an important enzyme in amino acid metabolism, is identical to a fatty acid-binding protein (FABPpm) isolated from plasma membranes of several cell types. Employing a monospecific polyclonal antibody to rat mAspAT, we have used immunogold electron microscopy to study the subcellular distribution of mAspAT in various mammalian tissues. Immunogold labeling of rat tissue sections embedded in LR Gold resin showed strong labeling of mitochondria in all tissues examined (viz. liver, pancreas, pituitary, spleen, heart, kidney, submandibular gland). In addition, strong and specific labeling was also observed at a number of non-mitochondrial sites including various locations in kidney, such as on cell surface in distal tubules and cortical collecting ducts, in condensing vacuoles, along cell boundaries between adjoining cells, and in endothelial cells lining capillaries in the glomerulus. Surface labeling due to mAspAT was also seen in arteriolar endothelial cells and in lymphocytes. These findings support the previous identification of mAspAT as both a mitochondrial enzyme and a plasma membrane protein. It is suggested that in accordance with its established role in other cells and tissues, the surface-located mAspAT in kidney and endothelial cells is involved in the fatty acid transport process. The dual-localization of mAspAT, as well as a large number of other mitochondrial proteins (viz. Hsp60, Hsp10, Cytochrome c, TRAP-1 and P32 (gC1q-R)) in recent studies, within both mitochondria and at various specific extramitochondrial sites raises fundamental questions about the role of mitochondria in cell structure and function, and about the mechanisms that exist in normal cells for protein translocation from mitochondria to other compartments. These results have implications for the role of mitochondria in apoptosis and different diseases.
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PMID:Immunogold localization of mitochondrial aspartate aminotransferase in mitochondria and on the cell surface in normal rat tissues. 1196 39

Cytochrome c release and mitochondrial permeability transition (MPT) play important roles in apoptosis. In this study, we found that selenium, an essential trace element, induced mitochondrial membrane potential (Delta psi(m)) loss, swelling, and cytochrome c release in isolated mitochondria. All of the above observations were blocked by cyclosporin A (CsA), which is a specific inhibitor to permeability transition pore (PTP), indicating selenite-induced mitochondrial changes were mediated through the opening of PTP. In physiological concentration, selenite could induce mitochondria at low-conductance PTP 'open' probability, which is correlated to regulate the physiological function, whereas in toxic concentration, induce mitochondria at high-conductance PTP 'open' probability and rapidly undergo a process of osmotic swelling following diffusion toward matrix as for inducer (Ca(2+)/P(i)). Selenite also induced other mitochondrial marker enzymes including monoamine oxidase (MAO) and mitochondria aspartate aminotransferase (mAST). Oligomycin inhibited the selenite-induced cytochrome c release and Delta psi(m) loss, showing that F(0)F(1)-ATPase was important in selenite or Ca(2+)/P(i)-induced MPT.
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PMID:Mitochondrial permeability transition and cytochrome c release induced by selenite. 1200 54

It has been reported that over-expression of GRP75 can protect cells under different types of stress. In this study, we investigated the protective effect of GRP75 on the liver both in vivo and in vitro. To evaluate the effect of GRP75 over-expression on oxidative damage in the liver in vitro, cell viability and the mitochondrial function of GRP75-overexpressing HL-7702 cells and control transfected cells were monitored during H(2)O(2) treatment. In vivo, liver fibrosis was induced in rats by carbon tetrachloride (CCl(4)) injection for 8 weeks. The GRP75-overexpressing vector was randomly injected into rats before fibrosis was established to study the inhibitory effect of GRP75 on hepatic fibrosis. Liver injury and mitochondrial function were assessed. On H(2)O(2) treatment, GRP75-overexpressing HL-7702 cells exhibited more moderate cell damage than control HL-7702 cells. Both groups of cells showed a decrease in ATP following an early increase on H(2)O(2) treatment, and the mitochondrial membrane potential also decreased similarly in these two groups of cells. Control HL-7702 cells showed an immediate and rapid increase in reactive oxygen species accumulation after the onset of H(2)O(2) treatment, and this accumulation was slowed and reduced in GRP75-overexpressing cells. Western blotting revealed that cytochrome c was greater in control HL-7702 cells than in GRP75-overexpressing HL-7702 cells. Compared with the CCl(4)-only rats, serum alanine transaminase and aspartate aminotransferase were significantly lower in CCl(4)-treated rats transfected with the GRP75 vector (P < 0.01). ATP concentrations decreased in both groups of rats treated with CCl(4), but were higher in the GRP75-overexpressing CCl(4)-treated group than in CCl(4)-only rats. Cytochrome c expression was lower in GRP75-overexpressing rats than in CCl(4)-only rats.
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PMID:Over-expression of GRP75 inhibits liver injury induced by oxidative damage. 2328 70