TEMPERATURE DEPENDENCE OF ATP HYDROLYSIS BY LOACH EMBRYONIC CELLS Na+/K+-ATPase UNDER THE INFLUENCE OF He-Ne LASER

2016 ◽  
Vol 18 (2) ◽  
pp. 88-93
Author(s):  
M. S. Romaniuk ◽  
◽  
S. M. Mandzynets ◽  
M. V. Bura ◽  
D. I. Sanagursky ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Atp Hydrolysis ◽  
Embryonic Cells

Free energy and enthalpy of ATP hydrolysis in the sarcoplasm

1969 ◽  
Vol 174 (1036) ◽  
pp. 348-353 ◽  
Keyword(s):  
Free Energy ◽  
Ionic Strength ◽  
Temperature Dependence ◽  
Thermodynamic Data ◽  
Approximate Calculation ◽  
Atp Hydrolysis ◽  
Equilibrium Conditions ◽  
Thermodynamic Measurements

A rigorous calculation of the free energy available in vivo from ATP hydrolysis requires the following information which is not all available, namely: (i) intra­cellular pH, (ii) activities of all the species of reactants and products in sarcoplasm, (iii) thermodynamic data for all the reactions involved, including values for ionic strength and temperature dependence, and (iv) the extent of deviation from equilibrium conditions, i. e. during contraction. We shall discuss each of these factors in turn and state the assumptions made that allow the approximate calculation of the free energy made available by the following net reaction in the sarcoplasm: ATP +H 2 O → ADP + Pi + H + . (1) Although it can only be an approximation this calculation is useful since it will take into account recent thermodynamic measurements in vitro .

scholarly journals The Ca2+-transporting ATPases of rabbit and trout exhibit different pH- and temperature-dependences

1993 ◽  
Vol 293 (2) ◽  
pp. 469-473 ◽  
Author(s):  
E N Chini ◽  
F G de Toledo ◽  
M C Albuquerque ◽  
L de Meis
Keyword(s):  
Temperature Dependence ◽  
Atp Hydrolysis ◽  
Ph Dependence ◽  
Atp Synthesis ◽  
Amino Acid Residues ◽  
Specific Amino Acid ◽  
Temperature Dependences ◽  
Temperature Ranges ◽  
Similar Temperature ◽  
Membrane Bound

The phosphorylation of the trout sarcoplasmic-reticulum Ca(2+)-ATPase by Pi differs in its temperature- and pH-dependence from the rabbit ATPase. In the trout enzyme, the apparent affinity for Pi and maximum phosphoenzyme values do not vary over a pH and temperature ranges that have a pronounced effect on the rabbit enzyme. The lack of temperature-dependence for phosphorylation is observed at pH 6.8. At pH 8.0, the temperature profile for phosphorylation of the trout enzyme resembles that of the rabbit at pH 6.8. The rabbit ATPase is no longer phosphorylated by Pi after solubilization with the detergent C12E9. In contrast, the trout enzyme can be phosphorylated by Pi after solubilization with C12E9, and the same levels of phosphoenzyme were obtained with the soluble and membrane-bound ATPase at both 0 degrees and 25 degrees C. In the range of 0-20 degrees C, the rates of ATP synthesis and of Ca2+ uptake by the trout ATPase are less temperature-dependent than for the rabbit enzyme. However, both isoenzymes catalyse ATP hydrolysis with similar temperature-dependences. The results raise the possibility that protonation of specific amino acid residues may contribute to the lack of temperature-dependence for phosphorylation of the trout Ca(2+)-ATPase.

scholarly journals A novel N-terminal extension in mitochondrial TRAP1 serves as a thermal regulator of chaperone activity

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
James R Partridge ◽  
Laura A Lavery ◽  
Daniel Elnatan ◽  
Nariman Naber ◽  
Roger Cooke ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Temperature Dependence ◽  
Atp Hydrolysis ◽  
Binding Pocket ◽  
Chaperone Activity ◽  
Regulatory Function ◽  
Protein Homeostasis ◽  
Closed State ◽  
Higher Eukaryotes ◽  
Rate Limiting

Hsp90 is a conserved chaperone that facilitates protein homeostasis. Our crystal structure of the mitochondrial Hsp90, TRAP1, revealed an extension of the N-terminal β-strand previously shown to cross between protomers in the closed state. In this study, we address the regulatory function of this extension or ‘strap’ and demonstrate its responsibility for an unusual temperature dependence in ATPase rates. This dependence is a consequence of a thermally sensitive kinetic barrier between the apo ‘open’ and ATP-bound ‘closed’ conformations. The strap stabilizes the closed state through trans-protomer interactions. Displacement of cis-protomer contacts from the apo state is rate-limiting for closure and ATP hydrolysis. Strap release is coupled to rotation of the N-terminal domain and dynamics of the nucleotide binding pocket lid. The strap is conserved in higher eukaryotes but absent from yeast and prokaryotes suggesting its role as a thermal and kinetic regulator, adapting Hsp90s to the demands of unique cellular and organismal environments.

scholarly journals Time dependence of atp hydrolysis by loach embryonic cells Na+/K+- ATPase under the influence of He-Ne laser

2015 ◽  
Vol 2015 (3) ◽  
pp. 13-19
Author(s):  
М. ROMANIUK ◽  
◽  
S. MANDZYNETS’ ◽  
М. BURA ◽  
D. SANAHURSKY ◽  
...  
Keyword(s):  
Time Dependence ◽  
Atp Hydrolysis ◽  
Embryonic Cells

scholarly journals Characterization of Ca2+ uptake and release by vesicles of skeletal-muscle sarcoplasmic reticulum

1987 ◽  
Vol 245 (3) ◽  
pp. 731-738 ◽  
Author(s):  
J M McWhirter ◽  
G W Gould ◽  
J M East ◽  
A G Lee
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Temperature Dependence ◽  
Atp Hydrolysis ◽  
Slow Phase ◽  
Second Phase ◽  
Release Process ◽  
Two Phases ◽  
Ph Range ◽  
Uptake And Release

Homogenization of muscle gives a preparation of sealed vesicles derived from the sarcoplasmic reticulum. In the presence of ATP these vesicles will initially accumulate Ca2+ from the external medium and then spontaneously release this Ca2+ in two phases, an initial slow phase and a faster second phase. By measuring ATP concentrations in parallel with measurements of external Ca2+ concentrations we have shown that the second phase of release occurs when the added ATP has been exhausted, but that the first phase of release occurs in the presence of ATP. A similar pattern of uptake and release has been observed in the presence of acetyl phosphate, showing that ADP generated by ATP hydrolysis is not essential for the release process. The temperature-dependence of both phases of release is similar to the temperature-dependence of ATPase activity. Release is dependent on pH over the same pH range as affects binding of Ca2+ to the ATPase. Therefore we propose that Ca2+ release from vesicles of sarcoplasmic reticulum actively loaded with Ca2+ is mediated by the same Ca2+ + mg2+-activated ATPase as is responsible for uptake of Ca2+.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

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