Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Escherichia coli O127:B8 lipopolysaccharide (LPS), prepared by the Westphal procedure, caused a marked decrease in the activities of mitochondrial malate dehydrogenase, succinate dehydrogenase, and adenylate kinase in African green monkey kidney (Vero) cells and primary cultures of mouse liver cells within 2 h after exposure to 10 micrograms of LPS/ml of culture medium. These three enzyme activities leaked into the supernatant fraction, and cytochrome oxidase activity was lost from the mouse liver mitochondrial particulate fraction within 45 min after exposure to 10 micrograms of LPS/mg of protein. Loss malate dehydrogenase activity from isolated mitochondria was also accelerated by LPS from E. coli O26:B6 (Boivin preparation) or Salmonella typhosa O901 (Westphal preparation), and by lipid A from Salmonella minnesota or Shigella sonnei. In addition, LPS and lipid A inhibited state 3 respiration by isolated mitochondria with attendant loss of respiratory control, but adenosine 5'-diphosphate/O ratios were relatively unchanged. Impaired mitochondrial function is an early event after exposure to biologically relevant amounts of LPS or lipid A.
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PMID:Action of bacterial endotoxin and lipid A on mitochondrial enzyme activities of cells in culture and subcellular fractions. 11 91

We show that a synthetic peptide corresponding to the N-terminal 22 residues of the cytochrome c oxidase subunit IV presequence blocked import of pre-subunit IV into yeast mitochondria. The 22-residue peptide pL4-(1-22) did not alter the electrical potential across the mitochondrial inner membrane (the delta psi). Inhibition of import was reversible and could be overcome by the addition of increased amounts of precursor. Two other peptides, pL4-(1-16) and pL4-(1-23), which correspond to, respectively, the N-terminal 16 and 23 residues of the same presequence, also blocked import of pre-subunit IV. However, pL4-(1-16) was a much weaker inhibitor of import, while the inhibitory effect of pL4-(1-23) was due to its ability to completely collapse the delta psi. pL4-(1-22) seems to be a general inhibitor of mitochondrial import, in that it also blocked uptake of several other proteins. These included the precursors of the yeast proteins cytochrome c oxidase subunit Va, the F1-ATPase beta subunit, mitochondrial malate dehydrogenase, and the ATP/ADP carrier. In addition, uptake of two non-yeast precursor proteins (human ornithine transcarbamylase and a cytochrome oxidase subunit IV-dihydrofolate reductase fusion), was also blocked by the peptide. Subsequent studies revealed that pL4-(1-22) did not block the initial recognition or binding of proteins to mitochondria. Rather, our results suggest that the peptide acts at a subsequent translocation step which is common to the import pathways of many different precursor proteins.
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PMID:A synthetic presequence reversibly inhibits protein import into yeast mitochondria. 216 Apr 69

In vivo administration of L-thyroxine (L-T4) in Anabas testudineus, while significantly stimulated the activities of cytochrome c oxidase and alpha-glycerophosphate dehydrogenase (alpha-GPDH), inhibited glucose-6-phosphate dehydrogenase (G-6-PDH), cytosolic and mitochondrial malate dehydrogenase (cyt. MDH; mit. MDH), and Mg2+ DNP-dependent adenosine triphosphatase (Mg2+ ATPase) activities. The activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and catalase remained unaltered after L-T4 treatment. Administration of protein synthesis inhibitors such as actinomycin D, while significantly inhibited cytochrome oxidase, alpha-GPDH, catalase, SDH, and Mg2+ ATPase activities, did not change LDH, cyt. MDH, and mit. MDH activities. Chloramphenicol injection significantly stimulated cytochrome oxidase, alpha-GPDH, and G-6-PDH activities. Simultaneous injections of actinomycin D or chloramphenicol with 3,5,3'-triiodo-L-thyronine (L-T3) or L-T4 prevented the effects of thyroid hormones on enzyme activities, when compared to the respective controls.
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PMID:Oxidative metabolism in a teleost, Anabas testudineus Bloch: effect of thyroid hormones on hepatic enzyme activities. 292 Sep 3

Changes in the maximal rate of some enzymatic activities related to energy transduction (lactate dehydrogenase; citrate synthetase and malate dehydrogenase; total NADH-cytochrome c reductase and cytochrome oxidase) and others such as glutamate dehydrogenase and acetylcholine esterase were assayed both in the purified mitochondrial fraction and in the crude synaptosomal fraction from the cerebral cortex of rats. The evaluations were performed before and after a postdecapitative normothermic ischaemia of 5, 10, 20 and 40 min duration. The ischaemic damage resulted in a decrease in the activity of mitochondrial malate dehydrogenase and total NADH-cytochrome c reductase, and of synaptosomal acetylcholine esterase. The biochemical evaluations were performed also after an intraperitoneal pretreatment with vincamine TPS, trimetazidine DC and suloctidil (50 mg/kg). These drugs induced different changes in enzyme activities as a function of the duration of ischaemia. These various interferences are discussed with regard to the possible mode of action of the drugs.
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PMID:Effect of ischaemia and pharmacological treatment on enzyme activities of cortical mitochondria and synaptosomes. 609 68

The activities of nine enzymes in liver specimens obtained from four children who had died from Reye's syndrome were compared to the corresponding activities of a control group of four children who had died from unrelated causes. At the 95% significance level, the alterations could be classified into three groups. Five activities [lactate dehydrogenase, alanine aminotransferase, glucose 6-phosphatase, cytochrome oxidase, and malate dehydrogenase (mitochondrial plus cytosolic)] showed no change. Three enzymes [glutamate dehydrogenase, isocitrate dehydrogenase (NADP), and monoamine oxidase] were decreased. One activity (glucose 6-phosphate dehydrogenase) was increased. The malate dehydrogenase isozymes were resolved by electrophoresis, and the two bands were stained and measured. The ratio of cytosolic:mitochondrial enzyme was significantly greater in Reye's syndrome than in the control group. These results lend further support to the view that in Reye's syndrome the impairment of hepatic function is largely confined to the mitochondria. The lowered activity of monoamine oxidase means that the abnormalities extend to the outer mitochondrial membrane. Imbalances of the cytosolic:mitochondrial enzyme activities were evaluated in needle biopsy specimens from four other children under conditions where neurologic abnormalities were less severe. Two patients had elevated ratios of both glutamate:lactate dehydrogenase and cytosolic:mitochondrial malate dehydrogenase activities, and a third had only an abnormal malate dehydrogenase ratio. In contrast to these Reye's syndrome patients, a fourth case admitted with a provisional diagnosis of Reye's syndrome showed no abnormality in either ratio in stage IV coma.
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PMID:Comparison of cytosolic and mitochondrial hepatic enzyme alterations in Reye's syndrome. 745 35

Changes in the maximal rate of some cerebral enzymatic activities related to energy transduction (lactate dehydrogenase; citrate synthase and malate dehydrogenase; total NADH-cytochrome c reductase and cytochrome oxidase) as well as both glutamate dehydrogenase and acetylcholine esterase were assayed in the purified mitochondrial fraction or in crude synaptosomal fraction from cerebral cortex. The evaluations were performed in rats before and after a postdecapitative normothermic ischemia of 5, 10, 20 and 40 min duration. The ischemic damage resulted in a decrease in the activity of mitochondrial malate dehydrogenase and total NADH-cytochrome c reductase, and of synaptosomal acetylcholine esterase. The biochemical evaluations were performed also after an i.p. pretreatment with vincamine, trimetazidine and suloctidil (50 mg/kg). The drugs induced different changes in enzyme activities as a function of the ischemia duration. These various interferences are discussed with regard to the possible drugs mode of action.
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PMID:The effect of ischemia and pharmacological treatment evaluated on synaptosomes and purified mitochondria from rat cerebral cortex. 2104 37