The effect of temperature on some calcium-binding properties of troponin C and calmodulin

1980 ◽  
Vol 58 (9) ◽  
pp. 683-691 ◽  
Author(s):  
William D. McCubbin ◽  
Maxwell T. Hincke ◽  
Cyril M. Kay
Keyword(s):  
Calcium Binding ◽  
Heat Stability ◽  
Troponin C ◽  
Effect Of Temperature ◽  
Spectroscopic Techniques ◽  
Binding Properties ◽  
Tyrosine Residues ◽  
Temperature Range ◽  
Skeletal Protein ◽  
The Difference

Some calcium-binding properties of skeletal and cardiac troponin C (TnC) have been measured as functions of temperature employing several physical and spectroscopic techniques. The degree of exposure of the tyrosine residues in brain calmodulin has also been determined by a new approach. Circular dichroism thermal unfolding profiles have been established for the three cases: metal-free protein, high-affinity sites filled, and fully saturated. In addition some thermodynamic parameters have been calculated for these reversible melting processes. It was found that the calcium-binding parameters n and K, where n is the fraction of the total conformational change and K is the apparent association constant, for both skeletal and cardiac TnC, did not vary significantly over the temperature range 10–38 °C, but at 50 °C differences became quite apparent, dramatically so in the case of the skeletal protein. The technique of thermal perturbation difference spectroscopy was applied to determine the degree of exposure of aromatic chromophores for the TnC(s) and calmodulin in the absence and presence of calcium. For skeletal TnC and calmodulin the results were in good agreement with previous observations, but the reduced degree of exposure of the tyrosine residues in cardiac TnC, in the absence of Ca2+, was contrary to the earlier work. Calcium-induced difference absorption spectra have been measured for the TnC(s) over the temperature range 10–70 °C. Cardiac TnC showed greater heat stability than its skeletal counterpart, in terms of the rate and the amount of change of the difference spectral maxima.

Effect of Temperature on Ozone Cracking of Butyl Rubbers

1968 ◽  
Vol 41 (5) ◽  
pp. 1294-1299 ◽  
Author(s):  
A. N. Gent ◽  
H. Hirakawa
Keyword(s):  
Crack Growth ◽  
Ozone Concentration ◽  
Effect Of Temperature ◽  
Segmental Mobility ◽  
Temperature Range ◽  
Styrene Copolymers ◽  
The Difference ◽  
Rates Of Growth ◽  
Rate Controlling Step ◽  
Butadiene Styrene

Abstract Rates of growth of single ozone cracks have been measured for vulcanizates of two butyl rubbers over the temperature range of 20-160° C. Over most of this range the rates are quantitatively related to the segmental mobility of the polymer and depend upon temperature in accord with the appropriate form of the WLF relation. The rates are also proportional to the concentration of ozone. It is therefore concluded that diffusion of ozone into the polymer before reaction is the rate-controlling step. This is contrasted with the behavior of butadiene styrene copolymers, for which rates of crack growth are also quantitatively related to the segmental mobility, but the rates are somewhat larger at equivalent mobilities and the dependence upon ozone concentration is smaller. The difference is attributed to different penetration distances before reaction in polymers containing low and high densities of reactive sites.

scholarly journals Calcium Binding Properties of C. elegance Troponin C Mutant

2000 ◽  
Vol 40 (supplement) ◽  
pp. S140
Author(s):  
T. Ueda ◽  
Y. Kajiwara ◽  
O. Yoshioka ◽  
H. Katuzaki ◽  
T. Murase ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Troponin C ◽  
Binding Properties

Amino acid sequences and calcium-binding properties of two isoforms of barnacle troponin C

Biochemistry ◽  
1991 ◽  
Vol 30 (3) ◽  
pp. 702-707 ◽  
Author(s):  
John H. Collins ◽  
Janet L. Theibert ◽  
Jean Marie Francois ◽  
C. C. Ashley ◽  
James D. Potter
Keyword(s):  
Amino Acid ◽  
Calcium Binding ◽  
Troponin C ◽  
Amino Acid Sequences ◽  
Binding Properties

scholarly journals The effect of temperature on the viscosity of air

1926 ◽  
Vol 113 (763) ◽  
pp. 233-237 ◽  
Keyword(s):  
Present Author ◽  
Effect Of Temperature ◽  
Appreciable Change ◽  
Temperature Range ◽  
Higher Temperature ◽  
The Difference ◽  
Experimental Values ◽  
Coefficient Of Viscosity ◽  
Slight Alteration

In a recent paper Prof. A. 0. Rankine has put forward a number of criticisms of the results obtained from, and the experimental method employed in, the determination of the temperature coefficient of viscosity of air by the present author. In the first place, a comparison is drawn between the author’s results and those of other observers in the lower part of the temperature range, and the conclusion is drawn therefrom that there is a possibility of an error of 3 percent, in the author’s measurements throughout the whole range of temperature used. This inference is reached from the figures quoted in Table II of Rankine’s paper, in which the temperature range from 15° to 183° C. is considered. That some difference exists between the author’s results and those of other observers in the lower part of the temperature range is clear, but it must again be emphasised that the values given for low temperatures are not experimental values, but were obtained by an extension of the graph (fig. 2) for higher temperature measurements to the value of the viscosity as given by Millikanj for room temperatures. A slight alteration of the curvature of this extension would make an appreciable change in the ratios η100/η15 and η183/η15 , but this would not be sufficient to account for the curvature at B in fig. 3 of the original paper. If the values of T ⅜ /η for Breitenbach’s results at 182° C. and 302° C. are plotted on this curve, they lie above the present results and on a curve which would intersect AB at about 600° C. That part of the difference is due to this cause seems to be indicated by the fact that the difference diminishes as the temperature rises. Thus at 300° C. the following values of η300/η15 are obtained by Breitenbach, the only other worker at this temperature, and the author. The figures used are those given by Rankine.

Effect of Temperature on Deactivation Force of Three Commercial NiTi Orthodontic Archwires

2014 ◽  
Vol 1025-1026 ◽  
pp. 325-329
Author(s):  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn ◽  
Nathaphon Tangit ◽  
Subongkoch Tongkoom
Keyword(s):  
Descriptive Analysis ◽  
Bending Test ◽  
Effect Of Temperature ◽  
Cross Sectional ◽  
Temperature Range ◽  
Significant Difference ◽  
Close Relationship ◽  
The Difference ◽  
Lower Temperature ◽  
Niti Wires

Objective: The purpose of this study was to investigate the transition temperature range (TTR) and the effect of temperatures at 10, 20, 30, 40, 50 and 60 °C on the deactivation force of three commercially available NiTi archwires. Materials and methods: Three different brands of NiTi archwires, NiTi OR (Ormco), NiTi GH (G&H) and NiTi H (Highland), with a cross sectional area of 0.016 x 0.022 inch2 were analysed for transformation temperature range (TTR) by using differential scanning calorimeter and load-deflection characteristics using a three-point bending test at temperatures of 10, 20, 30, 37, 40, 50 and 60 °C. Statistical Analysis: Descriptive analysis was used to calculate each variable and Kruskal Wallis test was performed to assess the difference in measurements among the three NiTi wires. P<0.05 was considered as statistical significant. Results: TTR showed austenitic temperature finish (Af) at 24.45 °C for NiTi OR, 27.55 °C for NiTi GH and 51.5 °C for NiTi H. The highest deactivation force was found in NiTi H followed by NiTi OR and NiTi GH at the temperatures below and higher than 37°C. There were siginificant differences (p<0.05) in the deactivation force of NiTi OR - NiTi H and NiTi GH - NiTi H at 10 °C and 20 oC, and NiTi GH – NiTi H and NiTi GH – NiTi OR at 30 °C and 37 °C. However, no significant difference was found among all NiTi wires at 40, 50 and 60 oC, except NiTi GH – NiTi H at 60 oC. A close relationship was found between temperature and unloading curves (deactivaton force); increase in the temperature led to an increase in the plateau of delivery deactivation force and decrease in temperature led to a decrease in the plateau of delivery deactivation force. Conclusion: The TTRs of commercial NiTi archwires are variable, expecially the austenitic finish temperature. The deactivation force increases in higher temperature and decreases in lower temperature.

scholarly journals Effect of calcium ions on the irreversible denaturation of a recombinant Bacillus halmapalus alpha-amylase: a calorimetric investigation

2003 ◽  
Vol 373 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Anders D. NIELSEN ◽  
Claus C. FUGLSANG ◽  
Peter WESTH
Keyword(s):  
Calcium Ions ◽  
Calcium Binding ◽  
Thermal Inactivation ◽  
Binding Constants ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Titration Calorimetry ◽  
Free Calcium ◽  
Enthalpy Changes ◽  
The Difference

The effect of temperature and calcium ions on the denaturation of a recombinant α-amylase from Bacillus halmapalus α-amylase (BHA) has been studied using calorimetry. It was found that thermal inactivation of BHA is irreversible and that calcium ions have a significant effect on stability. Thus an apparent denaturation temperature (Td) of 83 °C in the presence of excess calcium ions was observed, whereas Td decreased to 48 °C when calcium was removed. The difference in thermal stability with and without calcium ions has been used to develop an isothermal titration calorimetric (ITC) procedure that allows simultaneous determination of kinetic parameters and enthalpy changes of the denaturation of calcium-depleted BHA. An activation energy EA of 101 kJ/mol was found for the denaturation of calcium-depleted BHA. The results support a kinetic denaturation mechanism where the calcium-depleted amylase denatures irreversibly at low temperature and if calcium ions are in excess, the amylase denatures irreversibly at high temperatures. The two denaturation reactions are coupled with the calcium-binding equilibrium between calcium-bound and -depleted amylase. A combination of the kinetic denaturation results and calcium-binding constants, determined by isothermal titration calorimetry, has been used to estimate kinetic stability, expressed in terms of the half-life of BHA as a function of temperature and free-calcium-ion concentration. Thus it is estimated that the apparent EA can be increased to approx. 123 kJ/mol by increasing the free-calcium concentration.

Acetylene chemisorption at palladium: Effect of temperature and structure of the surface

1984 ◽  
Vol 49 (6) ◽  
pp. 1448-1458
Author(s):  
Josef Kopešťanský
Keyword(s):  
Work Function ◽  
Atomic Hydrogen ◽  
Effect Of Temperature ◽  
Thermally Stable ◽  
Template Effect ◽  
Temperature Range ◽  
Adsorbed Layers ◽  
Different Types ◽  
Adsorption Complexes ◽  
Low Coverage

The effect of temperature and structure of the palladium surfaces on acetylene chemisorption was studied along with the interaction of the adsorbed layers with molecular and atomic hydrogen. The work function changes were measured and combined with the volumetric measurements and analysis of the products. At temperature below 100 °C, acetylene is adsorbed almost without dissociation and forms at least two different types of thermally stable adsorption complexes. Acetylene adsorbed at 200 °C is partly decomposed, especially in the low coverage region. Besides the above mentioned effects, the template effect of adsorbed acetylene was studied in the temperature range from -80° to 25 °C. It has been shown that this effect is a typical phenomenon of the palladium-acetylene system which is not due to surface impurities.

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