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Topic: Denaturation (biochemistry)


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In the News (Sat 25 May 19)

  
  Denaturation | World of Biology
One common example of a denatured protein is egg albumin which changes from a gelatinous liquid to a solid when heated.
Denaturation occurs when proteins are exposed to strong acids or bases, high concentrations of inorganic salts, or organic solvents such as alcohol.
Some proteins may be renatured by exposing the denatured protein to a solution that approximates normal physiological conditions.
www.bookrags.com /research/denaturation-wob   (790 words)

  
  Biochemistry Encyclopedia   (Site not responding. Last check: )
Biochemistry is the study of the chemical processes and transformations in living organisms.
Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions (enzymes are a type of protein).
Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist.
www.hallencyclopedia.com /topic/Biochemistry.html   (3281 words)

  
 Encyclopedia
In biochemistry, denaturation is a structural change in biomolecules such as nucleic acids and proteins, such that they are no longer in their native state (the shape which allows for optimal biological activity).
This was important historically, as it led to the notion that all the information needed for proteins to assume their native state was encoded in the primary structure of the protein, and hence in the DNA that codes for the protein.
The denaturation of nucleic acids such as DNA, also called melting, is the separation of a double strand into two single strands, which occurs when the hydrogen bonds between the strands are broken.
encyclopedia.stylokna.pl /Denaturation_(Biochemistry)   (501 words)

  
  AllRefer.com - denaturation (Biochemistry) - Encyclopedia
Denaturation is defined as a major change from the original native state without alteration of the molecule's primary structure, i.e., without cleavage of any of the primary chemical bonds that link one amino acid to another.
Denaturation may be studied in the laboratory in any number of ways that monitor the physical properties of protein.
Denaturing is also used to describe the unrelated process of adding a poisonous substance to ethanol to make it unsuitable for human consumption.
reference.allrefer.com /encyclopedia/D/denatura.html   (330 words)

  
 ScienceDaily: Biochemistry Articles
Denaturation is the alteration of a protein shape through some form of external stress (for example, by applying heat, acid or alkali), in such a way that it will no longer...
In biochemistry, this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R...
In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance, called a catalyst, that is itself not consumed by the overall reaction.
www.sciencedaily.com /articles/matter_energy/biochemistry   (552 words)

  
 Unusual Property of Prion Protein Unfolding in Neutral Salt Solution
We suggest that an increase in the concentration of the anions on the surface of the prion protein molecule due to their preferential interaction with the glycine residues in the N-terminal segment destabilizes the structure of the prion protein by perturbing the prion helix 1 which is the most soluble of all the protein
In the presence of Na the temperature of thermal denaturation decreases, and the effect increases with the increase in the concentration of the salt (Figure 2a).
Figure 2 Thermal denaturation of (a) the full-length mouse prion protein and (b and c) the sheep prion protein, in buffer and in the presence of different salts.
pubs.acs.org /cgi-bin/jtextd?bichaw/41/36/html/bi025886t.html   (5950 words)

  
 Denaturation: Free Encyclopedia Articles at Questia.com Online Library
The forms of denaturation that attend the socio-historical processes...basic) and excessive (surplus) forms of denaturation, the former consequent upon social...himself argues that necessary and excess denaturation are not historically separable (81...
The presence of DNA denaturation in each cell was observed as a shift...chromatin is resistant to acid induced DNA denaturation and fluoresces green.
DENATURATION term used to describe the loss of native, higher-order...that alters the precise geometry is said to cause denaturation.
www.questia.com /library/encyclopedia/101240516   (906 words)

  
 BC Online: 2E - Lab. Determination of DelG Unfolding   (Site not responding. Last check: )
The denaturation curves usually show a sigmoidal, cooperative transition from the native to the denatured state.
A more realistic denaturation curve might show a linear change in the values of the dependent variable (fluorescence intensity for example) for values of temperature or denaturant concentration well below that at which the protein starts to unfold, or above that at which it is unfolded.
If temperature is the denaturing agent, the temperature at this point is called the melting point (Tm) of the protein, which is analogous to the Tm (in the heat capacity vs temperature graphs) for the gel to liquid crystalline phase transition of phospholipid vesicles.
employees.csbsju.edu /hjakubowski/classes/ch331/protstructure/oldelgodenature.html   (1003 words)

  
 Denaturation
Denaturation of nucleic acids was thought to be irreversible until 1961 [2].
Denaturation of DNA is usually achieved by heat treatment or high pH, which causes the double-stranded helix to dissociate into single strands.
Denaturation of DNA is a prerequisite for the hybridisation of originally double-stranded DNA with other nucleic acids [12].
www.sigmaaldrich.com /Brands/Fluka___Riedel_Home/Bioscience/BioChemika_Ultra/Denaturation.html   (424 words)

  
 Biochemistry
Biochemistry: is the study of the chemical composition and reactions of living matter.
Most forms of denaturation are reversible, however if the temperature change or Ph change is too sever the protein may be irreversibly denatured, that is, damaged beyond repair.
Denaturation is incompatible with the biologic function of the protein because it causes rearrangement of the protein’s active site.
www.etsu.edu /cpah/hsci/forsman/Biochemistry.htm   (2886 words)

  
 Denaturation (biochemistry) - QuickSeek Encyclopedia   (Site not responding. Last check: )
In biochemistry, denaturation is a structural change in biomolecules such as nucleic acids and proteins, such that they are no longer in their native state, and their shape which allows for optimal activity.
Proteins denature when they lose their three-dimensional structure - their chemical conformation and thus their characteristic folded structure.
Proteins may be denatured at the secondary, tertiary and quaternary structural levels, but not at the primary structural level.
denaturationbiochemistry.quickseek.com   (697 words)

  
 The Thermal Stability of Immunoglobulin: Unfolding and Aggregation of a Multi-Domain Protein -- Vermeer and Norde 78 ...
The denaturation of immunoglobulin G was studied by different calorimetric methods and circular dichroism spectroscopy.
Thermal denaturation of immunoglobulin G was studied by differential scanning calorimetry.
Conformation and thermal denaturation of apocalmodulin: rol of electrostatic mutations.
www.biophysj.org /cgi/content/full/78/1/394   (5578 words)

  
 Protein Chemistry of Albumen Photographs
Denaturation can also occur when a protein is exposed to high pressure, radiation and even sound waves.
Ovalbumin resists thermal denaturation but it is denatured by applying a mechanical force or by exposure to alcohol.
Based on the denaturation parameters of the albumen proteins, it is evident that all of the main albumen proteins are denatured during processing.
albumen.stanford.edu /library/c20/messier1991a.html   (3248 words)

  
 Unfolding Studies on Soybean Agglutinin and Concanavalin A Tetramers: A Comparative Account -- Sinha et al. 88 (2): ...
The protein sample was denatured in 6 M GdnCl and then renatured by dialyzing in 25 mM HEPES buffer for 12 h.
The GdnCl-induced denaturation curves for the lectins SBA and
Thermodynamics of denaturation of barstar: evidence for cold denaturation and evaluation of the interaction with guanidine hydrochloride.
www.biophysj.org /cgi/content/full/88/2/1300   (4309 words)

  
 JBMB Online [BSRK]
The stability of four hemoglobins (Hb) in dimer forms (low concentration) were investigated by the kinetics of denaturation.
The rate constants of denaturation were obtained by variation of 280 nm absorption versus time in 10 mM Tris-HCl, 10 mM EDTA, pH 8.0 at 45¡ÆC in the absence and presence of 0.5 M ethanol, dimethyl sulfoxide (DMSO), formamide, and glycerol.
As a matter of fact, this phenomenon is an indication of an increase in the denaturation capacity (DC) and hydrophobicity, and a decrease in the surface tension of the solution in the preceding co-solvents.
www.jbmb.or.kr /view_article.php3?cont=jbmb&kid=159&mid=6&pid=6   (203 words)

  
 Yale Scientific Magzine
Two Yale scientists, Lynne Regan, professor of molecular biophysics and biochemistry, and Andrew Miranker, associate professor of molecular biophysics and biochemistry, grapple with these issues in their investigations of the mysteries of protein folding.
This technique is utilized to generate denaturation curves, which track the unfolding of proteins tagged with GFP in heat denaturation, the disruption of structure at high temperatures.
Denaturation curves can provide valuable clues to protein folding-associated human diseases like Fragile X syndrome, the main cause of inherited mental retardation in humans.
research.yale.edu /ysm/article.jsp?articleID=456   (1591 words)

  
 PROTEIN STABILITY - 2
Cold Denaturation: Although, as we saw, the thermodynamics of protein folding predicts cold denaturation, in that the free energy curve starts to drop at lower temperatures, the initial idea for cold denaturation was based on experimental observation (the theory really came later).
Disulfide bonds are believed to increase the stability of the native state by decreasing the conformational entropy of the unfolded state due to the conformational constraints imposed by the cross-link (i.
Denatured States: I should maybe take a few moments to discuss the denatured state some more, because whether or not mutations affect the unfolded state is obviously an important question.
www.chemistry.ucsc.edu /~fink/200lecture/11-97.htm   (2303 words)

  
 BioMed Central | Full text | Improvement of Drosophila acetylcholinesterase stability by elimination of a free cysteine
We first analyzed denaturation with the most common methods used to study protein denaturation: incubation at high temperature or in the presence of urea.
It also provided resistance to urea denaturation: the mutated enzyme was 2.7-fold more stable than the wild type if we consider the ratio of half-life time in 4 M urea (Table 1).
All denaturation experiments were performed with 10 picomoles enzyme in 1 ml 25 mM phosphate buffer pH7 at 25°C. AChE was incubated in denaturing conditions and the remaining activity was measured by taking aliquots at regular times since residual enzymatic activity is dependent on the time of incubation.
www.biomedcentral.com /1471-2091/3/21   (3080 words)

  
 BioMed Central | Full text | The effect of engineered disulfide bonds on the stability of Drosophila ...
Protease was used as a denaturant because a protein's resistance to proteolysis increases with its conformational stability due to the fact that the susceptibly to proteolysis reflects the rate of local unfolding [21,22].
This instability has been interpreted as the result of atypical sets of dihedral angles in newly formed disulfide bridges [37], from stabilization of the denatured state [38] or from reduction of disulfide bonds followed by disulfide exchange or chemical reaction of the SH groups formed [39,40].
All denaturation experiments were performed with 10 picomoles enzyme in 1 ml 25 mM phosphate buffer pH7 at 25°C. AChE was incubated in denaturing conditions, aliquots were taken out at regular times, diluted 10-fold in enzyme reaction mixture and remaining activity was measured, since residual enzymatic activity is related to the proportion of non-denatured protein.
www.biomedcentral.com /1471-2091/7/12   (3043 words)

  
 Hilser Lab Research
However, whereas classic model development approaches seek to quantitatively capture a particular phenomena of interest, our unique approach is targeted toward the development of a model that possesses the properties of being; 1) simple, 2) experimentally verifiable, and 3) capable of unifying seemingly disparate observations within the context of a single formalism.
We are interested in the thermodynamic origins and consequences of conformational preferences in the denatured states of proteins, in particular the preference for the left-handed poly-proline II (PII) conformation.
Hamburger, J. Ferreon, J.C., Whitten, S.T and V.J. Hilser (2004) Thermodynamic Origins and Consequences of the Polyproline II (PII) Conformational Bias in the Denatured States of Proteins.
www.hbcg.utmb.edu /hilser/research.htm   (915 words)

  
 Protein Biochemistry: Evidence for Charged Amino Acids in Proteins
This lab demonstrates not only the reversible denaturation of a protein mixture, but provides evidence for the existence of electrical charges on the protein.
This might cause one region of a protein to "stick" to another region of the protein.
In this experiment, one will determine whether a purified solution of the protein casein will reversibly denature, and observe at which pH values the protein forms a precipitate.
www.accessexcellence.org /AE/AEC/AEF/1995/masterman_biochemistry.html   (901 words)

  
 Re: how does heat kill living things?
You can imagine that if all these proteins were to crumble and fall to pieces, due to heat or some other mechanism of denaturation, the cell wouldn't function very long.
When DNA is denatured, the strands of the double helix unzip and fall apart.
As you can imagine, once the nucleic acids are denatured, the organism is toast, so to speak.
www.madsci.org /posts/archives/nov2000/973532782.Bc.r.html   (171 words)

  
 Myoglobin+Microcalorimeter   (Site not responding. Last check: )
For the acid denaturation (pH 4.5), a heat of approximately 40 kcal/mole has to be assumed, which precisely balances the heat of uptake of hydrogen ions by the six histidine side chains which are abnormal in the native protein.
Further, there occurs denaturation at pH > 11.5, which is accompanied by a heat uptake of at least 30 kcal/mole.
An upper limit to this heat of denaturation could not be established, since the measurements could not be extended to a high enough pH.
hekto.med.unc.edu /HERMANS/OldPapers/MbCalorimeter1965.html   (249 words)

  
 Denaturation (biochemistry)
Denaturation is the alteration of a protein shape through some form of external stress (for example, by applying heat, acid or alkali), in such a way that it will no longer be able to carry out its cellular function.
Denatured proteins can exhibit a wide range of characteristics, from loss of solubility to communal aggregation.
Protein folding — Protein folding is the process by which a protein structure assumes its functional shape or conformation.
www.sciencedaily.com /articles/d/denaturation_(biochemistry).htm   (655 words)

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