scholarly journals Interaction of D-600 with the transmembrane domain of the sarcoplasmic reticulum Ca2+-ATPase

2000 ◽  
Vol 279 (1) ◽  
pp. C166-C172 ◽  
Author(s):  
Alicia Ortega ◽  
V. M. Becker ◽  
R. Alvarez ◽  
J. R. Lepock ◽  
H. Gonzalez-Serratos
Keyword(s):  
Thermal Stability ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Thermal Denaturation ◽  
Thermal Inactivation ◽  
Channel Blocker ◽  
Transmembrane Domain ◽  
Muscle Cells ◽  
The Stability ◽  
Thermal Stability Of

Experiments were performed to determine whether the organic Ca2+ channel blocker D-600 (gallopamil), which penetrates into muscle cells, affects sarcoplasmic reticulum (SR) Ca2+ uptake by directly inhibiting the light SR Ca2+-ATPase. We have previously shown that at 10 μM, D-600 inhibits LSR ATP-dependent Ca2+ uptake by 50% but has no effect on ATPase activity (21). These data suggest that the SR Ca2+-ATPase might be a potential target for D-600. The ATPase activity of the enzyme is associated with its hydrophilic cytoplasmic domain, whereas Ca2+ binding and translocation are associated with the transmembrane domain (18). In the present experiments, we determined which of the two domains of the ATPase is affected by D-600. Thermal inactivation experiments using the SR Ca2+-ATPase demonstrated that D-600 decreased the thermal stability of Ca2+ transport but had no effect on the stability of ATPase activity. In addition, D-600 at a concentration of 160 μM did not have any leaking effect of Ca2+ on the Ca2+-loaded SR. Thermal denaturation profiles of SR membranes revealed that D-600 interacts directly with the transmembrane domain of the Ca2+-ATPase. No evidence for interaction with the nucleotide domain was obtained. We conclude that the Ca2+ blocker D-600 inhibits the SR Ca2+ pump specifically by interacting with the transmembrane Ca2+-binding domain of the Ca2+-ATPase.

An unusual effect of NADP+ on the thermostability of the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase from Streptococcus mutans

2013 ◽  
Vol 91 (5) ◽  
pp. 295-302 ◽  
Author(s):  
Denis Arutyunov ◽  
Elena Schmalhausen ◽  
Victor Orlov ◽  
Sophie Rahuel-Clermont ◽  
Natalia Nagradova ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Streptococcus Mutans ◽  
Thermal Denaturation ◽  
Thermal Inactivation ◽  
Protein Molecule ◽  
Single Amino Acid ◽  
Binary Complex ◽  
Scanning Calorimetry ◽  
Active Centre ◽  
Thermal Stability Of

Adiabatic differential scanning calorimetry was used to investigate the effect of NADP+ on the irreversible thermal denaturation of the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Streptococcus mutans. The GAPN–NADP+ binary complex showed a strongly decreased thermal stability, with a difference of about 20 °C between the temperatures of the thermal transition peak maxima of the complex and the free protein. This finding was similar to the previously described thermal destabilization of GAPN upon binding of inorganic phosphate to the substrate binding site and can be interpreted as the shift of the equilibrium between 2 conformers of tetrameric GAPN upon addition of the coenzyme. Single amino acid substitution, known to abolish the NADP+ binding, cancelled the calorimetric effect of the coenzyme. GAPN thermal inactivation was considerably decelerated in the presence of NADP+ showing that the apparent change in stability of the active centre can be the opposite to that of the whole protein molecule. NADP+ could also reactivate the inactive GAPN* species, obtained by the heating of the apoenzyme below the thermal denaturation transition temperature. These effects may reflect a mechanism that provides GAPN the sufficient flexibility for the earlier observed profound active site reorganizations required during the catalytic cycle. The elevated thermal stability of the apoenzyme may, in turn, be important for maintaining a constant level of active GAPN — an enzyme that is known to be crucial for the effective supply of the reducing equivalents in S. mutans and its ability to grow under aerobic conditions.

Intrinsic Thermal Stability of Anisotropic Thin-Film Superconductors

1990 ◽  
Vol 112 (1) ◽  
pp. 10-15 ◽  
Author(s):  
M. I. Flik ◽  
C. L. Tien
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Stability Criterion ◽  
High Temperature Superconductors ◽  
Stability Criteria ◽  
Anisotropic Thermal Conductivity ◽  
Operating Current ◽  
Released Energy ◽  
The Stability ◽  
Thermal Stability Of

Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without resistance at all times after the occurrence of a localized release of thermal energy. This novel stability criterion is different from the cryogenic stability criteria for magnets and has particular relevance to thin-film superconductors. Crystals of ceramic high-temperature superconductors are likely to exhibit anisotropic thermal conductivity. The resultant anisotropy of highly oriented films of superconductors greatly influences their thermal stability. This work presents an analysis for the maximum operating current density that ensures intrinsic stability. The stability criterion depends on the amount of released energy, the Biot number, the aspect ratio, and the ratio of the thermal conductivities in the plane of the film and normal to it.

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

scholarly journals Change in the stability of goat milk and cow milk due to pH and heat

2021 ◽  
Vol 233 ◽  
pp. 02046
Author(s):  
Xiaoxue Fan ◽  
Ming Cheng ◽  
Xiaoning Zhang ◽  
Cunfang Wang ◽  
Hua Jiang
Keyword(s):  
Thermal Stability ◽  
Milk Production ◽  
Ph Value ◽  
Goat Milk ◽  
Cow Milk ◽  
Type B ◽  
Fresh Milk ◽  
Ph Conditions ◽  
The Stability ◽  
Thermal Stability Of

This paper aimed to evaluate the changes in the thermal stability of goat milk, cow milk and homogenized milk under different pH conditions. The results showed that goat milk was of type B milk, and the thermal stability were positively correlated with the pH value. But cow milk was of type A milk, the most stable pH of fresh milk was 6.9, while it was 6.7 for homogenized cow milk. Compared with cow milk, the acidification of goat milk was stronger due to heat. Therefore, in the process of milk production, the germicidal heating conditions of two different milk sources should be determined according to their thermal stability.

Thermal Stability of Strained InGaAs/GaAs Single Quantum Wells

1989 ◽  
Vol 160 ◽  
Author(s):  
B. Elman ◽  
Emil S. Koteles ◽  
P. Melman ◽  
C.A. Armiento ◽  
C. Jagannath
Keyword(s):  
Thermal Stability ◽  
Quantum Wells ◽  
Molecular Beam ◽  
Critical Thickness ◽  
Single Quantum ◽  
Furnace Annealing ◽  
Low Dislocation Density ◽  
The Stability ◽  
Thermal Stability Of ◽  
Low Temperature Photoluminescence

AbstractWe present a study of the structural stability of InGaAs/GaAs strained single quantum wells (SQW) grown with a variety of indium compositions and with well widths close to critical thickness values. The samples were grown by molecular beam epitaxy and were subjected to furnace annealing as well as ion implantation followed by rapid thermal annealing. Changes in low temperature photoluminescence linewidths were used to evaluate the stability of strained SQWs. We observed both strain relief, in wide SQWs and strain recovery, in higher indium composition narrow quantum wells which were partially relaxed (low dislocation density) as-grown.

Thermal Stability of Magnetic Properties in Dehydrogenated Triarylmethane Resins

1989 ◽  
Vol 173 ◽  
Author(s):  
Michiya Otani ◽  
Sugio Otani
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTThe stability of the magnetic properties of dehydrogenated triaryl-methane resins was investigated both at room temperature and at elevated temperatures. A magnetic property different from that reported in a previous paper was found in the course of studying the reproducibility of synthesis. This new property was examined through a mechanical response of the resins to a set of permanent magnets.

scholarly journals Differences in Thermal Stability of Glucosinolates in Five Brassica Vegetables

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S85-S88 ◽  
Author(s):  
M. Dekker ◽  
K. Hennig ◽  
R. Verkerk
Keyword(s):  
Thermal Stability ◽  
Brussels Sprouts ◽  
Pak Choi ◽  
Red Cabbage ◽  
Indole Glucosinolates ◽  
First Order Kinetics ◽  
Degradation Rates ◽  
Brassica Vegetables ◽  
The Stability ◽  
Thermal Stability Of

The thermal stability of individual glucosinolates within five different Brassica vegetables was studied at 100°C for different incubation times up to 120 minutes. Three vegetables that were used in this study were <I>Brassica oleracea</I> (red cabbage, broccoli and Brussels sprouts) and two were <I>Brassica rapa</I> (pak choi and Chinese cabbage). To rule out the influence of enzymatic breakdown, myrosinase was inactivated prior to the thermal treatments. The stability of three glucosinolates that occurred in all five vegetables (gluconapin, glucobrassicin and 4-methoxyglucobrassicin) varied considerably between the different vegetables. The degradation could be modeled by first order kinetics. The rate constants obtained varied between four to twenty fold between the five vegetables. Brussels sprouts showed the highest degradation rates for all three glucosinolates. The two indole glucosinolates were most stable in red cabbage, while gluconapin was most stable in broccoli. These results indicate the possibilities for plant breeding to select for cultivars in which glucosinolates are more stable during processing.

scholarly journals Gliadin Nanoparticles Pickering Emulgels for β-Carotene Delivery: Effect of Particle Concentration on the Stability and Bioaccessibility

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4188
Author(s):  
Ce Cheng ◽  
Yi Gao ◽  
Zhihua Wu ◽  
Jinyu Miao ◽  
Hongxia Gao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Active Ingredient ◽  
Functional Foods ◽  
Particle Concentration ◽  
Storage Conditions ◽  
Key Factors ◽  
Food Grade ◽  
The Stability ◽  
Thermal Stability Of ◽  
Β Carotene

β-carotene is a promising natural active ingredient for optimum human health. However, the insolubility in water, low oral bioavailability, and instability in oxygen, heat, and light are key factors to limit its application as incorporation into functional foods. Therefore, gliadin nanoparticles (GNPs) Pickering emulgels were chosen as food-grade β-carotene delivery systems. The objectives of the present study were to investigate the influence of GNPs concentration on the rheological properties, stability, and simulated gastrointestinal fate of β-carotene of Pickering emulgels. The formulations of Pickering emulgels at low GNPs concentration had better fluidity, whereas at high GNPs concentration, they had stronger gel structures. Furthermore, the thermal stability of β-carotene loaded in Pickering emulgels after two pasteurization treatments was significantly improved with the increase of GNPs concentration. The Pickering emulgels stabilized with higher GNPs concentration could improve the protection and bioaccessibility of β-carotene after different storage conditions. This study demonstrated the tremendous potential of GNPs Pickering emulgels to carry β-carotene.

Effect of osmolytes on the thermal stability of proteins: replica exchange simulations of Trp-cage in urea and betaine solutions

2018 ◽  
Vol 20 (16) ◽  
pp. 11174-11182 ◽  
Author(s):  
Beata Adamczak ◽  
Mateusz Kogut ◽  
Jacek Czub
Keyword(s):  
Thermal Stability ◽  
Molecular Mechanism ◽  
Thermal Denaturation ◽  
Replica Exchange ◽  
Thermal Stability Of ◽  
Denaturation Of Proteins

Although osmolytes are known to modulate the folding equilibrium, the molecular mechanism of their effect on thermal denaturation of proteins is still poorly understood.

Exercise prevents diabetes-induced impairment in superficial buffer barrier in porcine coronary smooth muscle

2004 ◽  
Vol 96 (3) ◽  
pp. 1069-1079 ◽  
Author(s):  
C. A. Witczak ◽  
M. Sturek
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Diabetic Dyslipidemia ◽  
Coronary Smooth Muscle ◽  
Treatment Groups ◽  
Analysis Techniques ◽  
Intracellular Ca

In healthy coronary smooth muscle cells, the superficial sarcoplasmic reticulum (SR) buffers rise in intracellular Ca2+ levels. In diabetic dyslipidemia, basal Ca2+ levels are increased, yet Ca2+ influx is decreased and SR Ca2+ uptake is increased. Exercise prevents diabetic dyslipidemia-induced increases in basal Ca2+ levels and decreases in Ca2+ influx. We tested the hypothesis that diabetic dyslipidemia impairs Ca2+ extrusion via a decrease in superficial SR and that exercise will prevent these losses. Male Yucatan swine were maintained in four treatment groups: control, hyperlipidemic, diabetic dyslipidemic, and diabetic dyslipidemic plus aerobically exercise trained. Intracellular Ca2+ levels were measured during depolarization-induced Ca2+ influx and caffeine-induced SR Ca2+ release. Na+/Ca2+ exchanger and plasmalemmal Ca2+-ATPase activity were assessed by inhibition with low extracellular Na+ and 5,6-carboxyeosin, respectively. Superficial SR was quantified using the internal membrane dye 3,3′-dihexyloxacarbocyanine iodide (DiOC6) and novel analysis techniques. We found that, in diabetic dyslipidemia, Ca2+ extrusion was impaired and superficial SR was decreased. Exercise prevented the diabetic dyslipidemia-induced decrease in superficial SR and restored plasmalemmal Ca2+ extrusion. On the basis of these results, we conclude exercise attenuates the diabetic dyslipidemia-induced impairment in intracellular Ca2+ regulation.

Sign in / Sign up

Export Citation Format

Share Document