Search results for "ATP"

Dysfunction of Torr causes a Harlequin-type ichthyosis-like phenotype in Drosophila melanogaster

2019

AbstractPrevention of desiccation is a constant challenge for terrestrial organisms. Land insects have an extracellular coat, the cuticle, that plays a major role in protection against exaggerated water loss. Here, we report that the ABC transporter Torr - a human ABCA12 paralog - contributes to the waterproof barrier function of the cuticle in the fruit fly Drosophila melanogaster. We show that the reduction or elimination of Torr function provokes rapid desiccation. Torr is also involved in defining the inward barrier against xenobiotics penetration. Consistently, the amounts of cuticular hydrocarbons that are involved in cuticle impermeability decrease markedly when Torr activity is redu…

S1/2 Mechanistic insights of F1-ATPase rotation from single-molecule measurements of the power stroke

2008

Hybridization and competition between the endangered sea marigold (Calendula maritima, Asteraceae) and a more common congener

2013

Occurrences of hybridization between the rare, endangered Sicilian endemic, Calendula maritima, and other congeners in the wild have been suspected by several authors, but never demonstrated. In San Cusumano (Trapani), one of the only three Sicilian mainland populations, C. maritima occurs in close proximity to the more common congener C. suffruticosa subsp. fulgida, and individuals morphologically intermediate between the two taxa have been observed. In order to determine whether hybridization is occurring at this site, and, if so, begin to assess the impact it could have on C. maritima, two independent tests of hybridity were conducted by studying (1) the pollen morphology and viability a…

Potential ATPase mimics by polyammonium macrocycles: Criteria for catalytic activity

1992

Abstract A series of polyammonium macrocycles, ranging in size from the 18-membered ring [18]aneN6 to the 36-membered [36]aneN12 were examined as potential ATPase mimics. The rates of hydrolysis of ATP were followed at pH 3.0 and 7.0 using 31P NMR and HPLC techniques. Stability constants as a function of degree of protonation, distribution curves for the ligands as a function of pH, and distribution curves for the mixed species of nucleotides, inorganic phosphate, and macrocycle were also determined. All of the macrocycles catalyzed the hydrolysis of ATP to some extent compared to noncatalyzed hydrolysis. A critical dependence on macrocyclic ring size was observed, with [21]aneN7 being the …

Solubilization of an oligomycin-sensitive ATPase complex fromRhodospirillum rubrumchromatophores and its inhibition by various antibiotics

1978

Estudio comparativo de los efectos electrofisiológicos miocárdicos intrínsecos de la apertura del canal KATP y del ejercicio físico crónico, en situa…

2015

El ejercicio físico aeróbico produce modificaciones electrofisiológicas como la depresión del automatismo sinusal, la conducción auriculoventricular, y modificaciones electrofisiológicas más recientemente estudiadas (refractariedad y heterogeneidad miocárdica), ligadas a la instauración de arritmias reentrantes. El ejercicio físico crónico ha sido propuesto por muchos autores como maniobra protectora no farmacológica antiarrítmica, pero los mecanismos precisos por los que el ejercicio físico crónico ejerce un efecto protector no se hallan totalmente dilucidados en la actualidad. Uno de los actuales enfoques para identificar los mecanismos básicos protectores, ha ido dirigido a la participac…

Zaburzenia metabolizmu miedzi w przebiegu choroby Wilsona

2022

Choroba Wilsona jest rzadką chorobą genetyczną charakteryzującą się zaburzonym metabolizmem miedzi. Dziedziczona jest w sposób autosomalny recesywny. Kluczowym organem odpowiedzialnym za metabo- lizowanie miedzi jest wątroba. Specyficzność substratową do jonów miedzi posiada białko transportowe ATP-aza typu P-ATP7B. Enzym przyczynia się do fizjologicznego transportu miedzi we wnętrzu komórki i jego wydalania z organizmu. Zmiany w genie kodującym białko ATP7B powodują nieprawidłowe funkcjonowania enzymu i brak jego współpracy z białkiem opiekuńczym ATOX1. W efekcie miedź nie zostaje przyłączona do ceruloplazminy oraz nie jest wydalana do jelit. Następuje gromadzenie pierwiastka we wnętrzu ko…

111 Bioluminescence analysis and numerical evaluation of ATP-synthesis by native and reconstituted membranes containing bacterial ATP-synthase

1992

ATP-synthase is a large membrane protein complex, which plays a key role in the energy metabolism of most organisms. It consists of at least eight types of subunits and can be isolated and purified from several organisms, e.g. bacteria. The enzyme couples two reversible reactions: vectorial proton transport through a membrane and synthesis of the energy rich molecule ATP. Both can be investigated with vesicles from native membranes or with reconstituted liposomes from purified ATPsynthase. The analysis is complicated because ATP-synthase catalyzes ATP-synthesis as well as ATP-hydrolysis. Furthermore the ATP level of membrane samples is influenced by adenylate kinase activities of other enzy…

Evidence for essential primary amino groups in a bacterial coupling factor F1ATPase.

1980

Abstract We have found that the binding of pyridoxal-5′-phosphate to 6 primary amino groups leads to the inactivation of the enzyme. A preferential reaction of pyridoxal-5′-phosphate with the α-subunits of this enzyme can be demonstrated. The reactivity of the amino groups is influenced by various effectors. In the presence of ATP the inhibition of the ATPase activity is noncompetitive.

3'-Arylazido-beta-alanyl-2-azido ATP, a cross-linking photoaffinity label for F1ATPases.

1989

Abstract The synthesis of the 3′-arylazido-2-azido ATP derivative 3′-O-{3-[N-(4-azido-2-nitrophenyl)-amino]propionyl}2-azido-adenosine 5′-triphosphate (2,3′-DiN3ATP) is described. The bifunc­ tional photoreactive ATP analog is characterized spectroscopically. Photoaffinity labeling of F, ATPase from Micrococcus luteus by this analog results in the inactivation of the enzyme and in the formation of higher molecular weight cross-links,