scholarly journals Calorimetric Study of Helix aspersa Maxima Hemocyanin Isoforms

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Svetla Todinova ◽  
Yuliana Raynova ◽  
Krassimira Idakieva
Keyword(s):  
Thermal Denaturation ◽  
Irreversible Process ◽  
Arrhenius Equation ◽  
Helix Aspersa ◽  
Thermal Unfolding ◽  
Calorimetric Study ◽  
Scanning Calorimetry ◽  
Scan Rate ◽  
Annealing Procedure ◽  
Helix Aspersa Maxima

The thermal unfolding of hemocyanin isoforms, β-HaH and αD+N-HaH, isolated from the hemolymph of garden snails Helix aspersa maxima, was studied by means of differential scanning calorimetry (DSC). One transition, with an apparent transition temperature (Tm) at 79.88°C, was detected in the thermogram of β-HaH in 20 mM HEPES buffer, containing 0.1 M NaCl, 5 mM CaCl2, and 5 mM MgCl2, pH 7.0, at scan rate of 1.0°C min−1. By means of successive annealing procedure, two individual transitions were identified in the thermogram of αD+N-HaH. Denaturation of both hemocyanins was found to be an irreversible process. The scan-rate dependence of the calorimetric profiles indicated that the thermal unfolding of investigated hemocyanins was kinetically controlled. The thermal denaturation of the isoforms β-HaH and αD+N-HaH was described by the two-state irreversible model, and parameters of the Arrhenius equation were calculated.

Irreversible thermal denaturation of Helix aspersa maxima hemocyanin

2018 ◽  
Vol 132 (1) ◽  
pp. 777-786 ◽  
Author(s):  
Svetla Todinova ◽  
Yuliana Raynova ◽  
Krassimira Idakieva
Keyword(s):  
Thermal Denaturation ◽  
Helix Aspersa ◽  
Helix Aspersa Maxima

scholarly journals A calorimetric study of the thermal denaturation of whey proteins in simulated milk ultrafiltrate

1977 ◽  
Vol 44 (3) ◽  
pp. 509-520 ◽  
Author(s):  
M. Rüegg ◽  
Ursula Moor ◽  
B. Blanc
Keyword(s):  
Heat Treatment ◽  
Xanthine Oxidase ◽  
Conformational Changes ◽  
Thermal Denaturation ◽  
Whey Proteins ◽  
Calorimetric Study ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Β Lactoglobulin ◽  
Dsc Thermograms

SummaryDifferential scanning calorimetry (DSC) was used to study thermal transitions of the following whey proteins and enzymes in milk ultrafiltrate solution: β-lactoglobulin, α-lactalbumin, serum albumin, γ-globulin, apo- and Fe-lactoferrin, lysozyme, ribonuclease, α-chymotrypsin and xanthine oxidase. Denaturation enthalpies (ΔHD), denaturation temperatures (TD) and the half width of the denaturation peaks in DSC thermograms (ΔT½D) were determined and the degree of renaturation was estimated by rescanning previously denatured samples. A fair correlation between the results obtained by DSC and other more classical methods was found in general. However, for some proteins (α-lactalbumin, lysozyme, ribonuclease and xanthine oxidase), which have so far been considered relatively thermostable, calorimetry reveals conformational changes starting at temperatures as low as about 45 °C. In these cases thermostability observed after heat treatment of milk should be interpreted in terms of renaturation and not of high temperatures of denaturation.

scholarly journals Effect of tartaric acid on conformation and stability of human prostatic phosphatase: an infrared spectroscopic and calorimetric study.

2001 ◽  
Vol 48 (3) ◽  
pp. 755-762 ◽  
Author(s):  
S Bem ◽  
W S Ostrowski
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Tartaric Acid ◽  
Solution Structure ◽  
Prostatic Acid Phosphatase ◽  
Thermal Unfolding ◽  
Calorimetric Study ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

The solution structure and thermal stability of human prostatic acid phosphatase (hPAP) in the absence and in the presence of tartaric acid were studied by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The temperature dependence of the infrared spectrum and DSC scans indicate that hPAP undergoes thermal unfolding at a temperature between 49.5 and 52.5 degrees C. Binding of tartaric acid does not lead to major changes in the secondary structure of hPAP, however, hPAP with bound tartaric acid shows a significantly increased thermal stability. These results helped to better understand the mechanism of hPAP unfolding at the elevated temperature.

scholarly journals Differential-scanning-calorimetric study of the irreversible thermal denaturation of 8 kDa cytotoxin from the sea anemone Radianthus macrodactylus

1994 ◽  
Vol 299 (3) ◽  
pp. 731-733 ◽  
Author(s):  
G G Zhadan ◽  
V L Shnyrov
Keyword(s):  
Thermal Denaturation ◽  
Kinetic Constant ◽  
Sea Anemone ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Study ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Rate Dependent ◽  
Scan Rate ◽  
State Kinetic

A differential-scanning-calorimetric study of the thermal denaturation of a sea-anemone (Radianthus macrodactylus) 8 kDa cytolytic toxin was carried out. The calorimetric traces were found to be irreversible and scan-rate-dependent under the experimental conditions employed. Scan-rate-dependent thermograms were explained in terms of a two-state kinetic model N k -->D, where k is a first-order kinetic constant that changes with temperature as given by the Arrhenius equation, N is the native state of the toxin, and D the denatured one.

scholarly journals Characteristics of Reconstituted Collagen Fibers from Chicken Keel Cartilage Depends on Salt Type for Removal of Proteoglycans

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3538
Author(s):  
Anna Pudło ◽  
Szymon Juchniewicz ◽  
Wiesław Kopeć
Keyword(s):  
Electron Microscopy ◽  
Rheological Properties ◽  
Thermal Denaturation ◽  
Surface Structures ◽  
Scanning Calorimetry ◽  
Cartilage Extracellular Matrix ◽  
Oscillatory Rheometry ◽  
Freeze Dried ◽  
Basic Features ◽  
Scanning Electron

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.

Differential scanning calorimetric study of the thermal unfolding of the motor domain fragments of Dictyostelium discoideum myosin II

1998 ◽  
Vol 251 (1-2) ◽  
pp. 275-280 ◽  
Author(s):  
Dmitrii I. Levitsky ◽  
Michael A. Ponomarev ◽  
Michael A. Geeves ◽  
Valery L. Shnyrov ◽  
Dietmar J. Manstein
Keyword(s):  
Dictyostelium Discoideum ◽  
Myosin Ii ◽  
Motor Domain ◽  
Thermal Unfolding ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Study

scholarly journals Calorimetric study on Bi-Cu-Sn alloys

2019 ◽  
Vol 38 (2019) ◽  
pp. 541-546
Author(s):  
Jolanta Romanowska
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Temperature Interval ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Calorimetric Study ◽  
Calorimetric Investigation ◽  
Scanning Calorimetry ◽  
Scanning Electron

AbstractThe paper presents results of calorimetric investigation of the Bi-Cu-Sn system by means of differential scanning calorimetry (DSC) at the temperature interval 25-1250∘C, Values of liquidus, solidus and invariant reactions temperatures, as well as melting enthalpies of the selected alloys were determined. Microstructure investigation of the alloys were performed by the use of a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS).

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