Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of polyamines on F1-ATPase catalyzed reactions has been studied through the use of submitochondrial particles and F1-ATPase. ATP degradation catalyzed by submitochondrial particles and F1-ATPase was inhibited by spermine and spermidine. Spermine's inhibition was much greater than spermidine's effect. In contrast, P1-ATP exchange and succinate dependent ATP synthesis catalyzed by submitochondrial particles were both stimulated by spermine. The inhibition of ATPase activity by polyamines probably occurs through polyamine's replacement of Mg2+ on ATP, for the following reasons. (a) The ATPase activity inhibited by spermine was partially recovered when Mg2+ was added. (b) Spermine bound to ATP and phospholipids but not to F1-ATPase; yet spermine inhibited the ATPase reaction catalyzed by F1-ATPase, a protein free of phospholipid. (c) The binding of spermine to ATP was inhibited by Mg2+. The ATP content in polyamine-deficient cells definitely was lower than that in normal cells. On the basis of these results, the possible role of spermine in keeping the ATP concentration at a high level is discussed.
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PMID:Effect of polyamines on mitochondrial F1-ATPase catalyzed reactions. 253 Feb 10

Studies on the effects of polyamines on oligomycin-sensitive ATPase activity of ox heart submitochondrial particles showed that, of the polyamines tested, only spermine affected the enzyme activity. Spermine within the physiological concentration range increased the Vmax. of the enzyme, but the Km for ATP was virtually unaffected. Binding studies of [14C]spermine to submitochondrial particles, under the same conditions as used for the ATPase assay, showed that the spermine binds to submitochondrial particles in a co-operative way; Hill plots of the data gave a Hill coefficient of 2 and a Kd of 8 microM. When submitochondrial particles were treated with trypsin, ATPase was not stimulated by spermine and the amount of spermine bound concomitantly was drastically decreased. The ATPase activity of isolated F1-ATPase was not affected by spermine. Removal of the natural protein ATPase inhibitor did not suppress either the stimulation of the ATPase activity by spermine or the spermine binding to the particles. The results obtained suggested that the polyamine binds and acts at the level of the liaison between the coupling factor F1 and the membrane sector F0 of the ATPase complex.
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PMID:Spermine binding to submitochondrial particles and activation of adenosine triphosphatase. 623 25

The endogenous production of H2O2 in isolated rat intestinal mitochondria and oxidant induced damage to mitochondria were examined. There was an appreciable amount of H2O2 production in presence of succinate, glutamate and pyruvate, while the presence of rotenone with succinate further increased production. Superoxide generated by the X-XO system induced membrane permeability transition (MPT), calcium influx, lipid peroxidation and changes in membrane fluidity in mitochondria. A decreased mitochondrial ATPase activity and uncoupling of respiration was also observed. Spermine inhibited swelling induced by X-XO and also blocked the calcium influx and reversed the membrane fluidity changes.
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PMID:Enterocyte mitochondrial dysfunction due to oxidative stress. 1065 Jul 29

Polyamine content (PAs) often changes in response to abiotic stresses. It was shown that the accumulation of PAs decreased in roots treated for 24h with 200 mM NaCl. The role of polyamines (putrescine - PUT, spermidine - SPD and spermine - SPM) in the modification of the plasma membrane(PM) H(+)-ATPase (EC 3.6.3.6) and the vacuolar(V) H(+)-ATPase (EC 3.6.3.14) activities in cucumber roots treated with NaCl was investigated. 24h treatment of seedlings with 50 microM PUT, SPD or SPM lowered the activities of proton pumps in both membranes. The decreased H(+)-ATPase activity in plasma membranes isolated from the PA-treated roots was positively correlated with a lower level of PM-H(+)-ATPase CsHA3 transcript. However, transcript levels of PM-H(+)-ATPase CsHA2 and V-ATPase subunit A and c in roots treated with 50 microM PAs were similar to those in the control. Additionally, treatment of plants with salt markedly increased the activity of the PM- and V-H(+)-ATPases. However, exposure of plants to 20% PEG had no effect on these activities. These data suggest that, under salt stress conditions, the increase in H(+)-ATPase activities is caused mainly by the ionic component of salt stress. It seems that the main role of the PAs in the 24h salt-treated cucumber plants could be a result of their cationic character. The PA levels decreased when concentration of Na(+) increased, so action of PAs contributes to ionic equilibrium. Moreover, the decrease in the concentration of polyamines, which inhibit the PM-H(+)-ATPase and the V-H(+)-ATPase, at least under the studied conditions, seems to be beneficial. Thus, plants can increase salinity tolerance by modifying the biosynthesis of polyamines.
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PMID:The role of polyamines in the regulation of the plasma membrane and the tonoplast proton pumps under salt stress. 1985 11