Protein Denaturation

Protein Denaturation Denaturation is a change or modification in the structure of a protein molecule70. Additionally, denaturation is a process in which a protein or nucleic acid loses its tertiary structure and secondary structure by the application of some external pressure or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent or hot. If proteins in living cells are denatured, this causes disruption of cell activity and possible cell death. Denatured proteins can exhibit a variety of characteristics, from loss of solubility to communal aggregation. Denaturation in this sense is not used in the preparation of denatured alcohol industrial chemicals. The denaturation process sometimes takes place reversibly or irreversible depending on the cause, and proteins that experience denaturation will reduce their biological activity and reduce their solubility so that they precipitate easily71. A common example of the denaturation process is that when food is cooked, some proteins will be denatured. This is why hard-boiled eggs become tough and cooked meat becomes denser. A classic example, denaturation of egg white proteins. When fresh from the egg, the egg white is transparent and liquid. Cooking egg whites makes them opaque, forming a dense, interconnected mass. Denatured proteins can exhibit a variety of characteristics, from loss of solubility to communal aggregation. Communal aggregation is the phenomenon of the aggregation of hydrophobic proteins to come closer and form bonds between them, thereby reducing the area exposed to water. Most biological proteins lose their biological function when denatured. For example, enzymes lose their properties, because the substrate can no longer bind to the active site, and because the amino acid residues involved in stabilizing the substrates' transition state are no longer positioned to be able to do so.In many proteins (unlike egg white), denaturation is reversible (the proteins can regain their original form when the denaturation trigger is removed). This was important, because it led to the idea that all the information needed for proteins to assume their native form was encoded in the primary structure of the protein, and hence in DNA the code for the protein. Denaturation has positive and negative sides. The downside of denaturation : 1. Protein loses biological activity 2. Protein deposition 3. Proteins lose some functional properties The positive side of denaturation is: 1. Heat denaturation of trypsin inhibitors in legumes can increase the digestibility and biological availability of legume proteins. 2. Partially denatured protein is easier to digest, foaming and emulsifying properties are better than native protein. 3. Denaturation by heat is a prerequisite for making gel heat-induced proteins. Denaturation can be reversible if a protein is only subjected to gentle denaturing conditions, such as a slight change in pH. If these proteins are returned to their original environment, they can regain their natural higher structure in a process called renaturation. Unfortunately, renaturation is generally very slow or does not occur at all. The typical characteristics of denaturation are : 1. Loss of the natural properties of proteins (three-dimensional structure and function) 2. The process occurs cooperatively 3. Denaturing destroys weak bonds build 3D structures of proteins The factors that denature proteins include: 1. 2. 3. 4. 5. Heat, destroys hydrogen bonds and hydrophobic interactions and causes coagulation. Acids and bases, destroying salt bridges (electrostatic interactions) Organic solvents, damage hydrogen bonds Heavy metal ions, react with disulfide bonds and acidic amino acids Agitation, pulling the protein until it breaks the cross-links to form a solid Protein denaturation is a condition where proteins experience changes or destruction of their secondary, tertiary and quaternary structures. This denaturation can be caused by several factors including heating, acidic or alkaline conditions to the extreme, heavy metal cations and the addition of saturated salts. Heating can cause the breaking of hydrogen bonds that support the secondary and tertiary structure of a protein, causing the hydrophobic side of the polypentide side group to be exposed. This causes the solubility of the protein to decrease and eventually settle and clump, this event is called coagulation.