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)

Three apparently different modifications of submitochondrial particles (SMP) or ATP synthase preparations (complex V) inhibit oxidative phosphorylation and ATP-32Pi exchange activities, all of which are reversible by addition of mono- or dithiols. (a) Triphenyltin chloride inhibits ATP synthesis and hydrolysis without uncoupling. The inhibition by triphenyltin chloride is reversible by addition of beta-mercaptoethanol, dithiothreitol, or dihydrolipoamide. (b) Factor B is a water-soluble protein of Mr (11-12) X 10(3), contains a vicinal dithiol, and is required for energy transfer to and from F1-ATPase when tested with SMP-rendered factor B deficient by extraction with ammonia-ethylenediaminetetraacetic acid (EDTA) (AE-SMP). Treatment of factor B with mono- and dithiol modifiers, such as p-(chloromercuri)benzenesulfonate (PCMPS), Cd2+, or diazenedicarboxylic acid bis(dimethylamide) (diamide), inhibits factor B. This inhibition is reversed by addition to modified factor B of appropriate mono- and dithiol compounds. Preparations of AE-SMP are partially F1 deficient and partially uncoupled. The uncoupling can be repaired completely by addition of factor B or low levels of oligomycin, or to a large extent by addition of F1-ATPase + oligomycin sensitivity conferring protein. (c) SMP, AE-SMP, and complex V can be completely uncoupled by treatment at 30 degrees C with phenylarsine oxide, Cd2+, diamide, PCMPS, monobromobimane, and mono- and bifunctional maleimides. The uncoupling by these reagents is potentiated by membrane energization. Uncoupling by diamide is greater than or equal to 80% reversed by dihydrolipoamide or beta-mercaptoethanol, the former being much more potent. Dithiothreitol and dithioerythritol are poorly effective.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thiols in oxidative phosphorylation: inhibition and energy-potentiated uncoupling by monothiol and dithiol modifiers. 647 76

The Influence of energy transfer inhibitors of ATP synthase on the chlorophyll fluorescence quenching of thylakoids was studied by the saturation pulse method. Triphenyltin chloride (TPT) treatment could result in an increase of q(Q) and a decrease of q(E) of the thylakoids, but DCCD could not. This increase could be abolished when the deltapH across the thylakoid membrane was dissipated by uncouplers (1O mM NH(4)Cl plus 1&mgr;M nigericin) or in higher salt medium which could relieve localized protons on the thylakoid membrane. In the electron transport system of H(2)O right curved arrow PD(0X) or H(2)O right curved arrow PBQ coupled with PSII. The stimulatory effect of TPT on q(Q) also diminished. By the methods of modulated fluorescence and low temperature fluorescence measurement we observed that TPT markedly increased the imbalance of the distribution of light energy between PSI and PSII in favor of PSII. These results suggest that the CF(0) proton flow could influence the light energy distribution between the two photosystems. This might be materialized by the regulation of the membrane-localized protons on the photochemical efficiency of photosystem II.
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PMID:Effects of CF(0) Proton Flow on the Distribution of Light Energy Between PSI and PSII. 1223 97