Thermally induced proteins

These thermal analysis studies serve to establish a direct relationship between a heat-induced AR method and the reversal of formalin-induced intra- and intermolecular protein cross-links.10 2831 Further, while formalin-treatment provides thermal stability to RNase A, this stabilization is not sufficient to prevent thermally induced protein denaturation at temperatures (>100°C) typically used in heat-induced AR methods.32 34 The implications of this finding for the mechanism of AR will be discussed further in Section 15.6. 

DSC in biochemistry is the study of the energetics of thermally induced protein unfolding [276]. 

VJ Hilser, CD Worosila, E Freire. Analysis of thermal-induced proteins folding/ unfolding transitions using free-solution capillary electrophoresis. Anal. Biochem. 208 125-131 (1993). 

Shpigehnan, A. Israeli, G. Livney, YD. Thermally-induced protein-polyphenol co-assemblies Beta lactoglobulin-based nanocomplexes as protective nanovehicles for EGCG. Food Hydrocolloids 2010,24 (8), 735-743. 

FIGURE 13.13 Typical thermogram for thermally induced protein denaturation obtained hy DSC in which the denaturation temperature Td, the enthalpy of denaturation, and... 

Domike KR, Donald AM (2007) Thermal dependence of thermally induced protein spherulite formation and growth kinetics of p-lactoglobulin and insulin. Biomacromolecules... 

Hilser, V. J., Worosila, G. D., and Freire, E. (1993). Analysis of thermally induced protein foldingAinfolding transitions using free solution capihary electrt horesis, Ana/. Biochem. 208, 125-131. 

Bonsma S, Purchase R, lezowski S, Gallus J, Konz F, Volker S (2005) Green and red fluorescent proteins Photo- and thermally induced dynamics probed by site-selective spectroscopy and hole burning. Chemphyschem 6 838-849... 

J. Domanus, G. B. Strambini, and W. Galley, Heterogeneity in the thermally-induced quenching of the phosphorescence of multi-tryptophan proteins, Photochem. Photobiol. 34, 15-21 (1980). 

The results obtained with this procedure are similar to those previously reported in the literature by Hangartner, Hagenguth et al and Zeman et al (4, 2, 5, 6). The major exception, being the complete lack of alkylated pyrazines and alkylated thiophenes. These odour-intensive compounds arise from the thermal decomposition of proteins and sulphur containing amino acids. They also develop in the thermally induced reaction of proteins with carbohydrates (Maillard reaction). The authors indicated above have demonstrated that these compounds are invariably produced during the thermal treatment of sludge, a process which is not used in this Authority. 

Traditional sample preparation conditions to form SDS-protein complexes prior to electrophoretic analysis included heat treatment at elevated temperatures (e.g., In the case of non-reduced rMAbs, this could lead to sample preparation artifacts in the form of thermally induced fragmentation attributed to disulfide reduction and exchange reactions. Moreover, it was reported that high pH (>9.0) also enhanced the... 

Y Ishihama, Y Oda, N Asakawa, M Iwakura. Nanoscale monitoring of the thermally induced unfolding of proteins using capillary electrophoresis with in-column incubation. Anal. Sci. 13 931-938 (1997). 

Like any other protein, the molecular structure of the prion is subject to conformational flexibility and to various thermal-induced fluctuations between varying conformational states. However, if these fluctuations permit the PrP conformation to be attained, then this abnormal conformer promotes the widespread conversion of PrP to PrP , leading to the precipitous deposition of the abnormal protein throughout the brain (mirrored by the rapid and relentlessly downhill clinical course). This pathological self-propagating shape conversion of a-helical PrP to P-sheet PrP may in principle be initiated by a seed PrP molecule in the neurotoxic conformation. This explains the transmissibility of prion diseases and accounts for how susceptible humans exposed to beef from an animal with mad cow disease develop variant Creutzfeldt-Jakob disease. 

Fairwell, T., S. Ellis, and R.E. Lovins, Quantitative protein sequencing using mass spectrometry thermally induced formation of thiohydantoin amino acid derivatives from N-methyl- and N-phenylthiourea amino acids and peptides in the mass spectrometer. Anal Biochem, 1973. 53(1) 115-23. 

Figure 16.5 (a) The native folded state of the protein and the unfolded, denatured state following the thermally-induced structural change (b) the duplex state of nucleic acids, stable at low temperatures, in which the bases are paired and stacked, and the monomer states following the thermal disruption in which the bases are unpaired and randomly arranged along the backbone. 

Peptides formed enzymically or by mineral acid hydrolysis or thermal degradation of higher molecular veight protein can also serve as flavor precursors in thermally induced reactions. The reactivity of peptides is evidenced by their behavior during pyrolysis/GC (9), heating in air (10), reactions vith mono- (11), and dicarbonyl (12, 13) compounds and reactions in hot acetic acid (1A). The types of reactions observed for peptides include side-chain thermolysis, fragmentation into amino acids, DKP formation and Halliard reaction vith ambient carbohydrates. 

Globular storage proteins generally exhibit remarkable stability, especially thermal stability, which is common for proteins of the cupin superfamily. Globulins all share the tendency to form large thermally induced aggregates (heat-set gels), which form the basis of the widespread utilization of soy protein in foods (Mills et al. 2002). 

Coupling of maeroseopie and molecular investigations of thermally induced alterations of hairless mouse stratum corneum provide insight into molecular structure and barrier functions of the stratum corneum. Enhanced permeabilities below 70°C have been associated with increased lipid fluidity. However, the keratinized protein component of stratum corneum experiences only minor tertiary structural alterations with thermal pretreatments above 70°C. 

Thermally induced permeability enhancement of the more lipophilic solutes (butanol, octanol and hydrocortisone) through hairless mouse stratum corneum occurred in the temperature range also associated with lipid transitions in the calorimetry studies. Therefore, it seems likely enhanced permeabilities and lipid mobility within the stratum corneum are correlated. However, these macroscopic studies are unable to provide more specific information concerning the molecular origins of the thermal transitions. The studies provide even less information concerning possible irreversible alterations of the keratinized protein components of the stratum corneum. 

The sensitivities to temperature of all of these membrane-localized functions arise from the complex effects that temperature has on both the protein and lipid components of the membrane. Likely of greatest importance, however, are the effects of thermally induced changes in the physical states of lipids on the functions of proteins. Many aspects of thermal perturbation of membrane function—as well as key elements of the adaptive changes that occur in membrane lipids in response to change in temperature—... 

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