Extraction and Characterization of Proteins
Abstract
The experiment, entitled Extraction and Characterization of Proteins, aims to isolate casein from milk and albumin from egg; to explain the methods employed for protein extraction; to apply spectrophotometric methods in characterizing and quantifying extracted casein and albumin. The experiment was divided into 2 parts; the extraction of Albumin from egg and the determination of protein concentration via the Warburg-Christian method and Bradford Assay method. In the first part, egg white underwent the addition of a weak acid, disruption of cell membrane, addition of ammonium sulfate and centrifugation. The product obtained was not weighed because of its relatively small amount and was considered a failure by the experimenters. In the second part of the experiment, the protein concentration of the product acquired from the first part was calculated to be 5.1 mg/mL using the Warburg-Christian method. In the Bradford assay method, however, a negative value for the concentration was derived (-0.116) which led to the use of another solution provided by the instructor. The concentration of the new solution was determined to be 0.024 mg/mL using the Bradford assay method. The use of different solutions in the two methods accounts for the difference in protein concentration calculated. From these results, it can be concluded that the experiment failed to extract the desired amount of proteins, although it was shown that there are different relatively accurate ways in the determination of protein concentration.
Discussion Data and Results
Proteins are polymer organic molecules made up of monomers known as amino acids. First discovered in 1838, it was coined from the Greek word proteios, meaning primary—a word which describes its role in the composition of living organisms since it is the primary component of basic biological parts like the cell. Humans alone are composed of 15% proteins (Pauling et al, 1954) and have about 30,000 different kinds of
The experiment, entitled Extraction and Characterization of Proteins, aims to isolate casein from milk and albumin from egg; to explain the methods employed for protein extraction; to apply spectrophotometric methods in characterizing and quantifying extracted casein and albumin. The experiment was divided into 2 parts; the extraction of Albumin from egg and the determination of protein concentration via the Warburg-Christian method and Bradford Assay method. In the first part, egg white underwent the addition of a weak acid, disruption of cell membrane, addition of ammonium sulfate and centrifugation. The product obtained was not weighed because of its relatively small amount and was considered a failure by the experimenters. In the second part of the experiment, the protein concentration of the product acquired from the first part was calculated to be 5.1 mg/mL using the Warburg-Christian method. In the Bradford assay method, however, a negative value for the concentration was derived (-0.116) which led to the use of another solution provided by the instructor. The concentration of the new solution was determined to be 0.024 mg/mL using the Bradford assay method. The use of different solutions in the two methods accounts for the difference in protein concentration calculated. From these results, it can be concluded that the experiment failed to extract the desired amount of proteins, although it was shown that there are different relatively accurate ways in the determination of protein concentration.
Discussion Data and Results
Proteins are polymer organic molecules made up of monomers known as amino acids. First discovered in 1838, it was coined from the Greek word proteios, meaning primary—a word which describes its role in the composition of living organisms since it is the primary component of basic biological parts like the cell. Humans alone are composed of 15% proteins (Pauling et al, 1954) and have about 30,000 different kinds of
References: "Albumin." Microsoft® Student 2008 [DVD]. Redmond, WA: Microsoft Corporation, 2007. Biochemistry Laboratory Manual, UP Diliman Boyer, R.F. 1998. Concepts in Biochemistry. Brooks/ Cole Pub. Co. Hendrix, M.L. "Protein." Microsoft® Student 2008 [DVD]. Redmond, WA: Microsoft Corporation, 2007. Layne, E Linus P., R.B. Corey and R. Hayward. 1954. The Structure of Protein Molecules. Scientific American, Inc. McMurry, J. 2004. Organic Chemistry. Brooks/Cole, Thomson Learning, Inc.