Protein denaturation is a physical process that occurs when the three-dimensional structure of a protein is altered due to certain external conditions or factors. To understand this, it is important to note that a protein consists of different amino acids.
The unique folding pattern formed by the sequence of amino acids in a protein determines its three-dimensional structure known as its native state. The conventional temperature scale has been replaced by the Kelvin scale over time. However, the units of temperature counterpart on both scales are almost similar.
A. Raising the temperature
Raising the temperature of the solution will not denature a protein.
The term denature means to change something from its natural state. In biology, this refers to changing a protein such that it adopts an unnatural shape and loses its functionality. Some common examples of this include boiling an egg (the egg whites become solid) or curdling milk (the protein in the milk forms lumps).
The things that cause proteins to denature are called denaturing agents. These can include heat, high or low pH, or alcohol. However, one thing that will not cause a protein to denature is raising the temperature of the solution.
It is true that raising the temperature of a solution will increase molecular motion within the solution (contributing to kinetic energy), which increases the likelihood of collisions between molecules.
However, it does not change how strongly molecules are attracted to each other through interactions like hydrogen bonds, electrostatic attractions, etc. Thus, raising the temperature has no effect on whether molecules are attracted enough to form bonds with each other and become effectively locked into place in their “natural” structures (like proteins).
B. Adding urea
Adding urea will not denature a protein. Denaturation is the process by which proteins lose their native conformation, or form. The primary structure of the protein, however, remains unchanged.
Denaturation causes a loss of biological activity, and can be caused by a number of factors such as pH change, high temperatures or chemicals.
Urea is a chemical that is often used to denature proteins in laboratories. It does so by disrupting the hydrogen bonds between the amino acids that make up the protein, causing it to unfold and lose its three-dimensional shape. When urea is added to a solution containing a protein, the protein will denature.
The process of denaturation is a reaction in which the physical and chemical properties are changed when the protein is exposed to an environment that it is not able to tolerate. A protein can be denatured by heat, acid and alkali, organic solvents, heavy metals, chaotropic ions or high concentrations of salt. The amino acids are then changed to their zwitterionic form.
When urea is added it will reduce the hydrogen bonding between the amino acids. This means that the secondary structure of the protein is lost, which leads to a reduction in tertiary structure of the protein. The change in the secondary structure will mean that the tertiary structure is altered.
So adding urea does not denature a protein because it does not cause any changes in any of the structures of a protein. It does however affect its chemical properties as it alters its electrical charge.
C. Changing pH
Changing pH will not denature a protein. Proteins are made up of long chains of amino acids. These amino acids have a carboxyl group at one end and an amino group at the other end, giving them the name “amino acids”. When these two groups are separated, they have opposite charges. If the pH is too high or too low, it can cause the amino and carboxyl groups to separate and cause the protein to unfold.
The other choices do denature proteins. Adding heat to a solution causes water molecules to move faster and increases their kinetic energy. This energy can disrupt the bonds that hold proteins together.
Proteins are made up of amino acids. The side chains of these amino acids can be bound together to form different structures. Proteins are denatured when the bonds that hold these structures together are broken. When a protein is denatured, the biological function of that protein is lost.
There are several factors that can denature proteins:
Heat – Heat causes the protein structure to become disorganized. This can cause the bonds holding the structure together to break and the protein to become denatured.
Acidic pH – The amino acids in proteins have a pH range at which they work best. When a solution becomes too acidic, the proteins structure will begin to fall apart and become denatured.
Basic pH – Just like an acidic environment can cause proteins to be denatured, so too can a basic environment (basic environments have a high pH). Strong bases can cause proteins to be denatured by breaking their bonds.
Solute concentration – Proteins also prefer certain concentrations of solutes in solution. When this concentration is changed, it can cause some of the bonds holding the protein together to break and lead to its being denatured.
Alcohols – Alcohols can act as both acids and bases and therefore
D. Adding a denaturant such as formaldehyde or phenol
Adding a denaturant such as formaldehyde or phenol will not denature a protein. Some of the factors that can denature a protein include temperature, pH, and ionic strength.
Denaturation is the alteration of the protein’s tertiary structure. It affects the protein’s function because it changes its conformation, which means that it cannot perform its normal functions. The best way to prevent proteins from being denatured is to keep them in an environment where they will not lose their folded structure.
Last Words
In order to denature a protein, to cause its structure to change, it generally requires the application of excessive heat (around 150 degrees Celsius) or high pH chemicals. While a protein can be denatured by either an increase or decrease in temperature or pH, most commonly you will see conditions that fall within this range of optimal values: pH = 7.5, 60-70 C.