Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.41 (isocitrate dehydrogenase)
 3,101 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Flight by insects is characterized by the most intense respiration known in biology and also the most controlled. Thus insect flight muscle may be the tissue of choice for the study of biochemical adaptation in the control of catabolism and biological oxidations, and many of the results obtained with insects have a significance and a relevance that transcend the boundaries between classes. In insects, such as the blowfly, flight is distinguished additionally by high wingbeat frequencies and an asynchronous type of excitation-contraction coupling. In spite of this intense muscular work, metabolic processes are not limited by the availability of oxygen. Also of importance is the morphological organization of the flight muscle and mitochondria, which have evolved ultrastructurally and biochemically into an effective catabolic machine. 2. In the fly, carbohydrate, principally glycogen, is the sole metabolic fuel; fats are not used in flight and enzymes concerned with fatty acid utilization are virtually lacking. Glycogenolysis does not lead to lactic acid; instead, the end products of glycolysis are pyruvate and alpha-glycerophosphate. The alpha-glycerophosphate cycle provides a mechanism not only for the reoxidation of glycolytically produced NADH but also for the stoicheiometric formation from each molecule of hexose equivalent of two molecules of pyruvate, which are then available for oxidation via the tricarboxylate cycle. The absence of dicarboxylate and tricarboxylate carriers from the mitochondria ensures that tricarboxylate-cycle intermediates do not exit from the mitochondrion but that pyruvate is oxidized to completion. On initiation of flight, mitochondrial oxidation of pyruvate is impeded by the lack of tricarboxylate-cycle intermediates for the generation of oxaloacetate. This is circumvented by the oxidation of proline. 3. The controls on metabolism in flight muscle, i.e. (1) glycogenolysis at phosphorylase and phosphorylase kinase, (2) glycolysis at phosphofructokinase, (3) alpha-glycerophosphate dehydrogenase, (4) proline dehydrogenase and (5) tricarboxylate cycle at isocitrate dehydrogenase, are effected by the phosphate potential and/or Ca2+. It is suggested that the metabolic changes, such as those seen in the rest-to-flight transition, are achieved by the concerted actions of these effectors at the different loci.
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PMID:Biochemical adaptations for flight in the insect. 78 15

Embryo axes isolated from germinating lupine seeds were cultivated in vitro for 24-96 h over media containing either 60 mmol/L sucrose or no sucrose. Ultrastructural studies showed that large vacuoles were accumulating in a central region of primary parenchyma cells in sucrose starved lupine embryo axes, whereas cytoplasm along with organelles were forced to a periphery of the cells. We suggest that the autolysis of cytoplasmic proteins contributes to the accumulation of the vacuoles and this suggestion is consistent with the results of the characterisation of protein content. The level of cytosolic proteins was reduced by 50% and the activity of cytosolic marker enzyme, PEP carboxylase, was reduced by 46% in starved embryos as compared to control. The mitochondria from starved tissues were not degraded. The level of mitochondrial proteins was reduced by only 10% and the activity of mitochondrial NAD-isocitrate dehydrogenase decreased by 8% as a result of starvation. As demonstrated by the results of Percoll density gradient centrifugation, sucrose starvation caused an increase of 49% in many of the higher density mitochondria fractions, whereas many of the lower density mitochondria fractions were decreased by 33%. The samples of mitochondria from starved embryo axes were determined to have higher respiration activity in the presence of glutamate and malate as compared to control samples. EPR-based analyses of free radicals showed the presence of free radicals with a signal at g = 2.0060 in embryo axes. The level of the radical was two times higher in sucrose-starved embryo axes than in control (the level of this radical increased in senescing plant tissues as well). The results of EPR-based quantitation of Mn2+ ions revealed that the level was a few times higher in starved material than in control. Starved embryo axes, however, do possess a number of adaptive mechanisms protecting them from oxidative damage. Densitometric analyses of gels revealed an increase in the activity of SOD in sugar-starved embryos, whereas CAT and POX activities were lower in axes grown without sucrose as compared to control. Superoxide dismutase, catalase and peroxidase zymogram analyses showed that synthesis of new isoforms was not induced by sugar starvation. An accumulation of phytoferritin was found in plastids of sucrose starved embryos. These results are discussed in relation to the metabolic changes observed in senescing plant tissues.
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PMID:Metabolic and ultrastructural responses of lupine embryo axes to sugar starvation. 1274 88

The catabolic pathways and cellular responses of Pseudomonas putida P8 during growth on benzoate were studied through proteomics approach. Two-dimensional gel electrophoresis (2-DE) gel profiles of P. putida cells grown on 100 and 800 mg/L benzoate were quantitatively compared using threshold criteria and statistical tools. Protein spots of interest were identified through database searching based on peptide mass fingerprints (PMFs) obtained using matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Eight catabolic enzymes involved in both the ortho-cleavage (CatB, PcaI, and PcaF) and the meta-cleavage (DmpC, DmpD, DmpE, DmpF, and DmpG) pathways for benzoate biodegradation were identified in P. putida grown on 800 mg/L of benzoate while no meta-cleavage pathway enzymes were observed in the 2-DE gel profiles of P. putida grown on 100 mg/L of benzoate. The activation of both the ortho- and the meta-cleavage pathways in P. putida P8 grown on high benzoate concentration was confirmed directly at the protein level. In addition, another 28 differentially expressed proteins were also identified, including proteins involved in (i) detoxification and stress response (AhpC, ATPase-like ATP-binding region, putative DNA-binding stress protein, SodB and catalase/peroxidase HPI); (ii) carbohydrate, amino acid/protein and energy metabolism (isocitrate dehydrogenase, SucC, SucD, AcnB, GabD, ArcA, ArgI, Efp and periplasmic binding proteins of several ABC-transporters); and (iii) cell envelope and cell division (bacterial surface antigen family protein and MinD). Based on the data obtained, physiological changes of P. putida in response to growth on benzoate at different concentrations were discussed.
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PMID:Catabolic pathways and cellular responses of Pseudomonas putida P8 during growth on benzoate with a proteomics approach. 1898 Jan 83