Denaturation of Proteins
Almero, K. J. Date Due: 3 July 2013
Dante, R. A. Date Submitted: 3 July 2013 EXPERIMENT NO. 3 DENATURATION OF PROTEINS
Abstract
The experiment aimed to use the concept of viscosity to study the effects of different denaturants on 1% albumin extract. An Ostwald viscometer was used to measure the flow time of 5 mL of the blank and native protein. These were then denatured by adding 1 mL of denaturant and had their flow time measured. The flow time from the blank to denatured protein is increasing. The specific viscosity and reduced viscosity, ηred, were calculated from the data obtained. The best denaturant was determined based on the ηred of the denatured protein. NaCl had the highest percent change in viscosity from the native to denatured protein therefore it is the best denaturant for 1% albumin. The experiment can be deemed successful because of the high viscosity obtained in the results, indicating that the protein had been denatured as expected.
Results
Proteins are very sensitive to external conditions. To be able to preserve an extracted protein, one must know and maintain the favorable environmental conditions so that denaturation would be prevented. Denaturation is any alteration or modification in the native proteins’ secondary, tertiary or quaternary structure.1 Conditions that induced denaturation include pH changes, organic solvents, detergents, oxidation and reduction, salt concentration, metal ions, temperature changes and mechanical stress. For most researches and experiments, denaturation is avoided as much as possible because proteins have to be in their native/natural state. However, there are also circumstances wherein the proteins are
Dante, R. A. Date Submitted: 3 July 2013 EXPERIMENT NO. 3 DENATURATION OF PROTEINS
Abstract
The experiment aimed to use the concept of viscosity to study the effects of different denaturants on 1% albumin extract. An Ostwald viscometer was used to measure the flow time of 5 mL of the blank and native protein. These were then denatured by adding 1 mL of denaturant and had their flow time measured. The flow time from the blank to denatured protein is increasing. The specific viscosity and reduced viscosity, ηred, were calculated from the data obtained. The best denaturant was determined based on the ηred of the denatured protein. NaCl had the highest percent change in viscosity from the native to denatured protein therefore it is the best denaturant for 1% albumin. The experiment can be deemed successful because of the high viscosity obtained in the results, indicating that the protein had been denatured as expected.
Results
Proteins are very sensitive to external conditions. To be able to preserve an extracted protein, one must know and maintain the favorable environmental conditions so that denaturation would be prevented. Denaturation is any alteration or modification in the native proteins’ secondary, tertiary or quaternary structure.1 Conditions that induced denaturation include pH changes, organic solvents, detergents, oxidation and reduction, salt concentration, metal ions, temperature changes and mechanical stress. For most researches and experiments, denaturation is avoided as much as possible because proteins have to be in their native/natural state. However, there are also circumstances wherein the proteins are
References: [1] Switzer, R. and Garrity L. 1999. Experimental Biochemistry, 3rd ed.; United States of America: W. H. Freeman and Company. 89, 90 [2] Biochemistry Laboratory Manual, 2013 ed.; Quezon City: University of the Philippines – Diliman [3] White, A. 1973. Principles of Biochemistry, 5th ed.; United States of America: McGraw Hill Book Company. 162 [4] Campbell, M