Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malondialdehyde (MDA) is a product of oxidative damage to lipids, amino acids and DNA, and accumulates with aging and diseases. MDA can possibly react with amines so as to modify proteins and inactivate enzymes; it can also modify nucleosides so as to cause mutagenicity. Brain mitochondrial dysfunction is a major contributor to aging and neurodegenerative diseases. We hypothesize that MDA accumulated during aging targets mitochondrial enzymes so as to cause further mitochondrial dysfunction and additional contributions to aging and neurodegeneration. Herein, we investigated the neuronal mitochondrial toxic effects of MDA on mitochondrial respiration and activities of enzymes (mitochondrial complexes I-V, alpha-ketoglutarate dehydrogenase (KGDH) and pyruvate dehydrogenase (PDH)), in isolated rat brain mitochondria. MDA depressed mitochondrial membrane potential, and also showed a dose-dependent inhibition of mitochondrial complex I- and complex II-linked respiration. Complex I and II, and PDH activities were depressed by MDA at >or=0.2 micromol/mg; KGDH and complex V were inhibited by >or=0.4 and >or=1.6 micromol MDA/mg, respectively. However, MDA did not have any toxic effects on complex III and IV activities over the range 0-2 micromol/mg. MDA significantly elevated mitochondrial reactive oxygen species (ROS) and protein carbonyls at 0.2 and 0.002 micromol/mg, respectively. As for the antioxidant defense system, a high dose of MDA slightly decreased mitochondrial GSH and superoxide dismutase. These results demonstrate that MDA causes neuronal mitochondrial dysfunction by directly promoting generation of ROS and modifying mitochondrial proteins. The results suggest that MDA-induced neuronal mitochondrial toxicity may be an important contributing factor to brain aging and neurodegenerative diseases.
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PMID:Neuronal mitochondrial toxicity of malondialdehyde: inhibitory effects on respiratory function and enzyme activities in rat brain mitochondria. 1902 56

The present study addresses whether exercise during pregnancy in mouse alters mitochondrial function in the brains of the resultant offspring. We divided pregnant mice into four groups: a control group and groups of mice that exercised for 20 (E20m), 30 (E30m) and 40 min/d (E40m). The pregnant mice ran on a treadmill at 12 m/min, 5 d/week for a duration of 3 weeks. The protein expression of cytochrome c oxidase subunit Va (CVa) was downregulated in the offspring of the E20m group, unlike that in the control animals, whereas CVa expression was reserved in the E40m neonates. The F1-ATPase catalytic core (Core) protein expression levels were the highest in the E40m group neonates. Complex I, IV and ATPase activities were significantly lower in the E20m group than that in the control group neonates and were reserved in the E30m and E40m group neonates. The activities of citrate synthase and pyruvate dehydrogenase were consistent with those of complex I, IV and ATPase. Peroxisome proliferator-activated receptor-gamma coactivator 1-alpha, mitochondrial transcription factor A, nuclear respiratory factor-1 and mitochondrial DNA showed high levels of expression in the E40m neonates compared with the other groups. Malondialdehyde (MDA) levels in E40m neonates were higher than that in the controls but were lower than that in the E20m neonates. Finally, 40 min/d of maternal exercise improved mitochondrial function in the resultant pups and was concomitant with brain-derived trophic factor induction in the hippocampus, thereby functionally improving short-term memory.
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PMID:Maternal exercise during pregnancy affects mitochondrial enzymatic activity and biogenesis in offspring brain. 2322 20

Oophorectomy in adult rats affected cardiac mitochondrial function. Progression of mitochondrial alterations was assessed at one, two and three months after surgery: at one month, very slight changes were observed, which increased at two and three months. Gradual effects included decrease in the rates of oxygen consumption and in respiratory uncoupling in the presence of complex I substrates, as well as compromised Ca2+ buffering ability. Malondialdehyde concentration increased, whereas the ROS-detoxifying enzyme Mn2+ superoxide dismutase (MnSOD) and aconitase lost activity. In the mitochondrial respiratory chain, the concentration and activity of complex I and complex IV decreased. Among other mitochondrial enzymes and transporters, adenine nucleotide carrier and glutaminase decreased. 2-Oxoglutarate dehydrogenase and pyruvate dehydrogenase also decreased. Data strongly suggest that in the female rat heart, estrogen depletion leads to progressive, severe mitochondrial dysfunction.
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PMID:In female rat heart mitochondria, oophorectomy results in loss of oxidative phosphorylation. 2787 98