Protein Denaturation
DENATURATION OF PROTEINS
Abstract
The experiment was done to be able to understand how various denaturants such as HCl and NaOH affects proteins. It was observed that different denaturants act upon or denature protein differently. This was determined using the principle of viscometry. An Ostwald viscometer was used to measure the viscosity of the prepared native, blank, denatured native and blank with denaturant solutions. The time required for the said solutions to pass through the viscometer were recorded and their viscosities were then calculated using the data. Experimentally, urea was found to be the best out of the six denaturants that were used.
Results and Discussion
Proteins differ from each other by means of the amino acids that it contains. Each protein has its own biological function based on the way its components are arranged, thus, a change in the conformation of these components will cause a drastic change in its function. And when this happens, the protein is said to be denatured. Denaturation refers to the state wherein there is a disruption in the original conformation of the protein – that is the native state of the protein. Only the primary of structure of the protein remains unchanged during denaturation while the secondary, tertiary and quaternary structures are all affected. Denaturation is brought about by various kinds of physical and chemical means; this includes changes in pH and temperature, or the addition of organic compounds, detergents, metal ions, and alkaloid reagents. The bonds that stabilize a protein’s tertiary structure, its salt linkage, hydrogen bonds, disulfide linkage and hydrophobic interactions, once broken, disrupt the protein’s secondary and tertiary structure. Aside from the change in its biological function, other effects of denaturation include the decrease in the solubility of the protein and increase in its isoelectric pH.
The change in pH causes denaturation in a way that when the pH of the
Abstract
The experiment was done to be able to understand how various denaturants such as HCl and NaOH affects proteins. It was observed that different denaturants act upon or denature protein differently. This was determined using the principle of viscometry. An Ostwald viscometer was used to measure the viscosity of the prepared native, blank, denatured native and blank with denaturant solutions. The time required for the said solutions to pass through the viscometer were recorded and their viscosities were then calculated using the data. Experimentally, urea was found to be the best out of the six denaturants that were used.
Results and Discussion
Proteins differ from each other by means of the amino acids that it contains. Each protein has its own biological function based on the way its components are arranged, thus, a change in the conformation of these components will cause a drastic change in its function. And when this happens, the protein is said to be denatured. Denaturation refers to the state wherein there is a disruption in the original conformation of the protein – that is the native state of the protein. Only the primary of structure of the protein remains unchanged during denaturation while the secondary, tertiary and quaternary structures are all affected. Denaturation is brought about by various kinds of physical and chemical means; this includes changes in pH and temperature, or the addition of organic compounds, detergents, metal ions, and alkaloid reagents. The bonds that stabilize a protein’s tertiary structure, its salt linkage, hydrogen bonds, disulfide linkage and hydrophobic interactions, once broken, disrupt the protein’s secondary and tertiary structure. Aside from the change in its biological function, other effects of denaturation include the decrease in the solubility of the protein and increase in its isoelectric pH.
The change in pH causes denaturation in a way that when the pH of the
References: 1. Basic Biochemistry 3rd.ed. Rafelson, M.E., et.al. MacMilan Publishing Co.Inc., 1971. 2. Introduction to Organic and Biological Chemistry 4th ed. Baum, Stuart. MacMillan Publishing Company,1987. 3. Chemistry and the Living Organism 6th ed. Bloomfield, M.M., Stephens, L.J. John Wiley & Sons, 1996. 4. Two-dimensional electrophoresis and Immunological Techniques. Dunbar, Bonnie. Plenum Press, 1987. 5. Fundamentals of General, Organic, and Biological Chemistry 2nd ed. McMurry, J., Castellion, M. Prentice Hall, New Jersey, 1996. 6. Laboratory Exercise in Organic & Biological Chemistry 3rd ed. Baum, S.J., et al. Mac Millan Publishing Co. 1987 7. Biochemistry Zubay, J. Addison-Wesley Publishing Co. 1983 8. http://jchemed.chem.wisc.edu/jcesoft/cca/CCA2/MAIN/VISCLIQ/CD2R1.HTM Viscosity of Liquids Accessed on December 3, 2008