Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

An ATPase from anaerobic Lactobacillus casei has been isolated and 100-times purified. The 400 kDa enzyme molecule was found to have a hexagonal structure 10 nm in diameter composed of at least six protein masses. SDS-electrophoresis reveals four or, under certain conditions, five types of subunit, of apparent molecular masses 57 (alpha), 55 (beta), 40 (gamma), 22 (delta) and 14 (epsilon) kDa with stoichiometry of 3 alpha, 3 beta, gamma, delta, epsilon. The following features resembling F1-ATPases from other sources were found to be inherent in the solubilized L. casei ATPase. (i) Detachment from the membrane desensitizes ATPase to low DCCD concentrations and sensitizes it to water-soluble carbodiimide. (ii) Soluble ATPase is inhibited by Nbf chloride and azide, is resistant to SH-modifiers and is activated by sulfite and octyl glucoside, the activating effect being much stronger than in the case of the membrane-bound ATPase. Substrate specificity of the enzyme is also similar to that of other factors F1. Divalent cations strongly activate the soluble enzyme when added at a concentration equal to that of ATP. An excess of Mn2+, Mg2+ or Co2+ inhibits ATPase activity of F1, whereas that of Ca2+ induces its further activation. No other F1-like ATPases are found in L. casei. It is concluded that this anaerobic bacterium possesses a typical F1-ATPase similar to those in mitochondria, chloroplasts, aerobic and photosynthetic eubacteria.
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PMID:The F1-type ATPase in anaerobic Lactobacillus casei. 213 82

Divalent cations are divided into two groups in relation to their ability to promote ATP synthase catalyzed reactions. In the presence of Mg2+, the following pattern rules: (i) uncoupler-stimulated ATP hydrolysis of Rhodospirillum rubrum chromatophores which shows an optimum concentration of the divalent cation; (ii) ATP-induced proton pumping in chromatophores; (iii) light-induced ATP synthesis in chromatophores; (iv) no or very low ATPase activity of purified F1-ATPase unmasked by diethylstilbestrol or n-octyl beta-D-glucopyranoside. In the presence of Ca2+, the following pattern occurs: (i) no stimulation of the ATP hydrolysis in chromatophores by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone; (ii) no ATP-induced proton pumping; (iii) no light-induced ATP synthesis; (iv) a high ATPase activity of the purified F1-ATPase which is inhibited by diethylstilbestrol and n-octyl beta-D-glucopyranoside. Co2+, Mn2+, and Zn2+ are members of the "Mg2+-group", whereas Cd2+ is suggested to fall between the two groups. Intrinsic uncoupling of the membrane-bound ATP synthase has been suggested to account for the effect caused by Ca2+ in chloroplasts [Pick, U., & Weiss, M. (1988) Eur. J. Biochem. 173, 623-628]. Such an interpretation is consistent with our results on chromatophores. The uncoupling cannot occur at the level of the membrane since neither light-induced nor Mg-ATP-induced proton pumping is affected by Ca2+. A conformational change is suggested to be the reason for this intrinsic uncoupling, and it is proposed to be controlled by the diameters of the divalent cations (Ca2+ greater than Cd2+ greater than Mn2+ greater than Co2+ greater than Zn2+ greater than Mg2+).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Division of divalent cations into two groups in relation to their effect on the coupling of the F0F1-ATPase of Rhodospirillum rubrum to the protonmotive force. 248 79

Bidentate cobalt(III)tetraamine adenosine triphosphate [Co(NH3)4ATP] was investigated as an inhibitor of the beef heart mitochondrial F1-ATPase. The compound was found to have a mixed noncompetitive mechanism with a Ki of 0.4 mM and an alpha of 1.4 during ATP hydrolysis. Co(NH3)4ATP also noncompetitively inhibited ATP hydrolysis in the presence of bicarbonate. ITP hydrolysis was similarly affected. Co(NH3)4ATP was also used in dual inhibitor studies with adenylylimidodiphosphate (AMP-PNP) and azide; it was found to be mutually exclusive with AMP-PNP and azide. The compound also protected the F1 from modification by 4-chloro-7-nitrobenzofurazan. These results are discussed in terms of the regulation of the ATP hydrolysis reaction.
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PMID:The effect of Co(III)(NH3)4ATP on the kinetics of beef heart mitochondrial ATPase. 285 40

Atomic absorption and electron paramagnetic resonance spectroscopy were used to study the metal binding sites of beef heart mitochondrial ATPase (F1). Quantitative and qualitative properties of these sites are described. Two different separation techniques were able to distinguish two very tight sites from one tight (easily exchangeable) metal binding site on F1. Of these sites, two are specific for magnesium while one can be substituted with Mn2+, Co2+, or Zn2+. When MgAMP-PNP was incubated with F1, a fourth metal was bound to the enzyme. The carboxyl group modified by dicyclohexylcarbodiimide is shown not to be involved in binding of any of the tightly bound metals. Qualitative properties of the metal binding sites using the Mn2+-enzyme complex as a probe were ascertained using EPR at pH 6.8 and 8.0. CrATP and Mn2+ appear to bind to different metal sites on F1. The possible role of the metals in regulation of catalysis, and their relation to nucleotide binding is discussed.
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PMID:Metal interactions with beef heart mitochondrial ATPase. 286 Jan 5

F1-ATPase of rat liver was examined for its capacity to interact with both metal ions and nucleotides and for the effect of covalent ATPase inhibitors on these interactions. As isolated, rat liver F1 contains about 2 mol of Mg2+/mol of F1, 1 mol of which can be removed or exchanged. The remaining mole of Mg2+ per mole of F1 remains very tightly associated with F1 and is recovered in the alpha gamma fraction after cold denaturation. Rat liver F1 also contains as isolated a nearly equivalent amount of nucleotide (approximately 1.7 mol/mol of F1) which is readily removed by incubation at room temperature followed by column centrifugation. The "2 Mg2+ enzyme" binds almost 3 mol of 5'-adenylyl imidodiphosphate (AMP-PNP)/mol of F1 in the presence or absence of added divalent cation. When divalent cation is present as Co2+, an equivalent activator to Mg2+ in the ATPase reaction, 1 mol of F1 binds 3 mol of both AMP-PNP and Co2+. under these conditions, the very tight Mg2+ site remains loaded, the exchangeable Mg2+ site is replaced with AMP-PNPCo, and two additional AMP-PNPCo sites are filled. At this point, ADP can be loaded onto the enzyme as a fourth nucleotide at a site separate and distinct from the AMP-PNP sites. Significantly, rat liver F1 contains only a single readily detectable ADP binding site in the presence or absence of divalent cation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ligand binding studies of the F1 moiety of rat liver ATP synthase: implications about the enzyme's structure and mechanism. 288 76

A facile and high-yield synthesis of a new ATP analogue, 2-[(4-azido-2-nitrophenyl)amino]ethyl triphosphate (NANTP), is described. NANTP and ATP are hydrolyzed by skeletal myosin subfragment 1 (SF1) at comparable rates in the presence of Ca2+, Mg2+, or NH4+-EDTA. NANTP is also cleaved but less readily by mitochondrial F1-ATPase and by (Na+ + K+)-ATPase from dog brain and hog kidney. F-Actin markedly activates NANTP cleavage by SF1 in the presence of Mg2+, suggesting that the diphosphate product NANDP is slow to be released from the enzyme. [alpha-32P]NANDP binds to a single site on SF1 (KA = 1 X 10(6) M-1) with an affinity identical with that of ADP. The absorption maximum of NANDP was shifted from 474 to 467 nm upon binding to SF1, suggesting that the purine binding site has a dielectric constant of about 45. NANDP was trapped in nearly stoichiometric amounts at the active site by cross-linking SH1 and SH2 with N,N'-p-phenylenedimaleimide (pPDM) or by chelation with cobalt (III) phenanthroline [Wells, J., & Yount, R. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 4966]. The trapped [beta-32P]NANDP X SF1 complex, like the comparable ADP X SF1 complex, was stable for days at 0 degree C and could be purified free of extraneous analogue by ammonium sulfate precipitation and gel filtration. Photolysis of the purified complex gave greater than 50% covalent incorporation of the trapped NANDP into the 95-kilodalton (kDa) heavy chain of SF1. Limited trypsinization and analysis by gel electrophoresis showed that greater than 95% of the bound label was associated with the 25-kDa NH2-terminal peptide. Without trapping, NANDP labeling of SF1 was nonspecific and was not prevented by addition of a large excess of ATP. This new approach of trapping photoaffinity analogues by cross-linking agents before photolysis may prove to be of general usefulness in increasing the specificity and extent of labeling of enzymes that undergo substrate-induced conformation changes.
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PMID:2-[(4-Azido-2-nitrophenyl)amino]ethyl triphosphate, a novel chromophoric and photoaffinity analogue of ATP. Synthesis, characterization, and interaction with myosin subfragment 1. 407 91

Purified F1-ATPase from Micrococcus lysodeikticus contains zinc in the amount of 1 mol/mol of enzyme. This zinc content correlates with standard values of ATPase activity (assayed with Ca2+-ATP as substrate) of the protein, i.e. 5--6 mumol substrate hydrolysed . min-1 . mg-1. Prolonged dialysis against EDTA results in a zinc-free protein which concomitantly loses its ATPase activity. Chelators such as Zincon, EDTA and L-cysteine inhibit the ATPase activity in concentration and/or time dependence related to their affinity for the metal ion involved. Reconstitution of the metallo (Zn2+) protein is demonstrated by the incorporation to the zinc-free protein of 65Zn2+ in amount near the 1 mol/mol of enzyme. This incorporation was concomitant with the regain of ATPase activity. The inhibition by EDTA and Zincon is reversed specifically by Zn2+ while the inhibition by EDTA is prevented by Zn2+ and Mn2+ and to, a minor extent, by Cd2+. Zn2+ and Ca2+ ions are involved and are probably mandatory in the ATPase activity of M. lysodeikticus F1 but their roles appear to be different and not exchangeable. Other divalent metal ions inhibit the Ca2+-ATPase activity of the Zn2+ protein by the following decreasing order; Hg2+, Fe2+, Co2+, Cd2+, Mn2+, Mg2+. M. lysodeikticus F1-ATPase is thus identified as a metallo (zinc) protein, which requires additional divalent metal ions for ATP hydrolysis.
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PMID:Identification of a bacterial energy-transducing ATPase as a metallo (Zn2+) protein. Effect of chelating agents and divalent metal ions on ATPase activity. 621 May 27

The effects of anions on the ATPase activity of submitochondrial particles from mouse liver cells were investigated. Thiocyanite decreased the ATP hydrolysis, acting as a competitive inhibitor with respect to sulfite. All the anions tested changed the ATPase activity noncompetitively towards Mg-ATP. The hydrolysis of CTP, GTP, ITP and UTP was insensitive to sulfite and thiocyanate. In the presence of Mn2+, Ca2+, Co2+, Zn2+ and Ba2+ an anion-dependent hydrolysis of ATP took place. It was assumed that the anions control the rate of the limiting step of the ATPase reaction, since sulfite and thiocyanate change the activation energy of ATP hydrolysis. The data obtained are discussed in terms of a previously proposed mechanism of the anions effect on the activity of mitochondrial ATPase.
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PMID:[Effect of anions on the ATPase activity of submitochondrial particles]. 621 16

The soluble F1-ATPase from the thermophilic bacterium PS3 (TF1) contains no endogenous adenine nucleotides and contains about 0.2 g ions of Mg2+/mol which resists removal by repeated centrifugation-elution on columns of Sephadex G-50. The isolated enzyme will not bind additional Mg2+ added in the absence of adenine nucleotides nor is the rate of inactivation of the isolated enzyme by dicyclohexylcarbodiimide (DCCD) affected by the addition of Mg2+. When ADP is added to isolated TF1, a 1:1 TF1 X ADP complex is formed which is stable to repeated gel permeation on columns of Sephadex G-50 subjected to centrifugation-elution. On formation of the 1:1 TF1 X ADP complex, the rate of inactivation of the enzyme by DCCD is accelerated 6-fold. The rate of inactivation of the 1:1 TF1 X ADP complex by DCCD is not further stimulated in the presence of 2 mM ADP which indicates that the binding of ADP to a single site in the enzyme is sufficient to promote maximal stimulation of the inactivation. Addition of Mg2+ to the 1:1 TF1 X ADP complex results in the binding of about 1 g ion of Mg2+/mol of enzyme. The 1:1:1 TF1 X ADP X Mg2+ complex thus formed is sluggishly inactivated by DCCD. When the Mg2+ is removed from the TF1 X ADP X Mg2+ complex by treatment with trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, the rate of inactivation of the enzyme by DCCD is accelerated 4-fold. Other divalent metal ions protect the 1:1 TF1 X ADP complex against inactivation by DCCD. Of these, Mn2+, Zn2+, Co2+, and Cd2+, which are about as equally effective as Mg2+ as cofactors for the hydrolytic reaction when present at 0.2 mM, offer about equal protection of the complex against inactivation by DCCD also when present at 0.2 mM. These results indicate that the binding site for ADP in the 1:1 TF1 X ADP complex is a catalytic site. TF1, inactivated by 92% with DCCD, has the same capacity to bind ADP as the active enzyme, forming a tight 1:1 TF1 X ADP complex which is stable to repeated centrifugation-elution on columns of Sephadex G-50. The 1:1 TF1 X ADP complex retains its capacity to bind Mg2+ to form the 1:1:1 TF1 X ADP X Mg2+ complex after it is inactivated by 88% with DCCD.
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PMID:Modulation by ADP and Mg2+ of the inactivation of the F1-ATPase from the thermophilic bacterium, PS3, with dicyclohexylcarbodiimide. 622 24

A post-translational processing assay of the precursor to the yeast F1-ATPase subunit has been utilized to examine a mitochondrial endoprotease which cleaves this subunit precursor to the size of a mature subunit. The endoprotease is extracted from purified mitochondria as a soluble complex of Mr = 115,000 which is composed of subunits of lower molecular weight when examined on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It exhibits a pH optimum of between pH 7 and 8 and is inactive at pH 6.5 and below. The mitochondrial endoprotease is insensitive to serine esterase inhibitors, but is inhibited by EDTA and o-phenanthroline. Restoration of precursor subunit processing activity in the presence of metal chelators is strictly dependent on excess Co2+ and Mn2+ over other heavy metals examined. These and additional data indicate that this soluble metallo endoprotease is involved in the processing of other cytoplasmically synthesized precursor subunits of the ATPase complex in addition to the subunit 2 precursor. The role of this processing enzyme in the assembly of mitochondrial inner membrane complexes is discussed in light of the current model of mitochondrial biogenesis.
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PMID:A neutral metallo endoprotease involved in the processing of an F1-ATPase subunit precursor in mitochondria. 646 Jul 66


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