scholarly journals Heat, Cold and Pressure Induced Denaturation of Proteins

2003 ◽  
Vol 17 (2-3) ◽  
pp. 367-376 ◽  
Author(s):  
G. Panick ◽  
H. Herberhold ◽  
Z. Sun ◽  
R. Winter
Keyword(s):  
Infrared Spectroscopy ◽  
Secondary Structure ◽  
Structural Properties ◽  
Relaxation Technique ◽  
Cold Denaturation ◽  
Unfolded State ◽  
Fouriertransform Infrared Spectroscopy ◽  
Monomeric Proteins ◽  
Kinetics Of ◽  
Denaturation Of Proteins

We studied the pressureinduced unfolding and refolding of monomeric proteins, such as SNase, αchymotrypsin and ubiquitin, by using synchrotron Xray smallangle scattering and Fouriertransform infrared spectroscopy, which monitor changes in the tertiary and secondary structural properties of the proteins upon pressurization. Furthermore, by using the pressurejump relaxation technique in combination with timeresolved Xray diffraction and infrared spectroscopy, the kinetics of the unfolding/refolding of the proteins, was investigated. Significant differences in secondary structure and chain compactness in the folding/unfolding reactions of these proteins are observed. The results are compared with data obtained from other methods of denaturation, such as heat and pressure-assisted cold denaturation. The cold- and pressure-induced unfolding both yield a particularly unfolded state characterized by a persistent amount of secondary structure.

Cold denaturation of yeast phosphoglycerate kinase: Kinetics of changes in secondary structure and compactness on unfolding and refolding

Biochemistry ◽  
1993 ◽  
Vol 32 (30) ◽  
pp. 7747-7752 ◽  
Author(s):  
Klaus Gast ◽  
Gregor Damaschun ◽  
Hilde Damaschun ◽  
Rolf Misselwitz ◽  
Dietrich Zirwer
Keyword(s):  
Secondary Structure ◽  
Phosphoglycerate Kinase ◽  
Cold Denaturation ◽  
Kinetics Of

scholarly journals Investigation by Synchrotron Radiation Circular Dichroism of the Secondary Structure Evolution of Pepsin under Oxidative Environment

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 998
Author(s):  
Laetitia Théron ◽  
Aline Bonifacie ◽  
Jérémy Delabre ◽  
Thierry Sayd ◽  
Laurent Aubry ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Secondary Structure ◽  
Proteolytic Activity ◽  
Digestive Enzyme ◽  
Structure Evolution ◽  
Food Protein ◽  
Maldi Tof ◽  
Kinetics Of ◽  
Circular Dichroïsm

Food processing affects the structure and chemical state of proteins. In particular, protein oxidation occurs and may impair protein properties. These chemical reactions initiated during processing can develop during digestion. Indeed, the physicochemical conditions of the stomach (oxygen pressure, low pH) favor oxidation. In that respect, digestive proteases may be affected as well. Yet, very little is known about the link between endogenous oxidation of digestive enzymes, their potential denaturation, and, therefore, food protein digestibility. Thus, the objective of this study is to understand how oxidative chemical processes will impact the pepsin secondary structure and its hydrolytic activity. The folding and unfolding kinetics of pepsin under oxidative conditions was determined using Synchrotron Radiation Circular Dichroism. SRCD gave us the possibility to monitor the rapid kinetics of protein folding and unfolding in real-time, giving highly resolved spectral data. The proteolytic activity of control and oxidized pepsin was investigated by MALDI-TOF mass spectrometry on a meat protein model, the creatine kinase. MALDI-TOF MS allowed a rapid evaluation of the proteolytic activity through peptide fingerprint. This study opens up new perspectives by shifting the digestion paradigm taking into account the gastric digestive enzyme and its substrate.

Analyzing the kinetics of fatigue fracture in polyethylene by infrared spectroscopy

1977 ◽  
Vol 12 (5) ◽  
pp. 805-807 ◽  
Author(s):  
A. M. Leksovskii ◽  
B. Gaffarov
Keyword(s):  
Infrared Spectroscopy ◽  
Fatigue Fracture ◽  
Kinetics Of

scholarly journals Chicken Intestinal Alkaline Phosphatase

1960 ◽  
Vol 43 (6) ◽  
pp. 1149-1169 ◽  
Author(s):  
M. Kunitz
Keyword(s):  
Alkaline Phosphatase ◽  
Zinc Ions ◽  
Magnesium Ions ◽  
Intestinal Alkaline Phosphatase ◽  
Reversible Inactivation ◽  
Higher Temperature ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Zn Ions ◽  
Denaturation Of Proteins

Purified chicken intestinal alkaline phosphatase is active at pH 8 to 9, but becomes rapidly inactivated with change of pH to 6 or less. Also, a solution of the inactivated enzyme at pH 4.5 rapidly regains its activity at pH 8. In the range of pH 6 to 8 a solution of purified alkaline phosphatase consists of a mixture of active and inactive enzyme in equilibrium with each other. The rate of inactivation at lower pH and of reactivation at higher pH increases with increase in temperature. Also, the activity at equilibrium in the range of pH 6 to 8 increases with temperature so that a solution equilibrated at higher temperature loses part of its activity on cooling, and vice versa, a rise in temperature shifts the equilibrium toward higher activity. The kinetics of inactivation of the enzyme at lower pH and the reactivation at higher pH is that of a unimolecular reaction. The thermodynamic values for the heat and entropy of the reversible inactivation and reactivation of the enzyme are considerably lower than those observed for the reversible denaturation of proteins. The inactivated enzyme at pH 4 to 6 is rapidly reactivated on addition of Zn ions even at pH 4 to 6. However, zinc ions are unable to replace magnesium ions as cocatalysts for the enzymatic hydrolysis of organic phosphates by alkaline phosphatase.

A calorimetric approach to the kinetics of the irreversible thermal denaturation of proteins

1992 ◽  
Vol 199 ◽  
pp. 147-157 ◽  
Author(s):  
María L. Galisteo ◽  
Francisco Conejero-Lara ◽  
Josefa Núñez ◽  
Jose M. Sánchez-Ruiz ◽  
Pedro L. Mateo
Keyword(s):  
Thermal Denaturation ◽  
Kinetics Of ◽  
Denaturation Of Proteins

scholarly journals Two-Dimensional Infrared Spectroscopy of Antiparallel β-Sheet Secondary Structure

2004 ◽  
Vol 126 (25) ◽  
pp. 7981-7990 ◽  
Author(s):  
Nurettin Demirdöven ◽  
Christopher M. Cheatum ◽  
Hoi Sung Chung ◽  
Munira Khalil ◽  
Jasper Knoester ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Secondary Structure ◽  
Two Dimensional ◽  
Two Dimensional Infrared Spectroscopy ◽  
Β Sheet
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