Extraction and Characterization of Proteins
EXTRACTION AND CHARACTERIZATION OF PROTEINS
Abstract
Different techniques and principles for protein extraction and characterization were demonstrated in this experiment. Various proteins were extracted from different sources: 1.67 g yeast invertase, 1.03 g egg white albumin, and 5.15 g of milk casein. Activity assay for invertase was performed using Benedict’s test and the enzymes inverting action on sucrose was confirmed. Warburg-Christian Method and Bradford Assay were also employed to determine the protein concentration in the albumin and the casein samples. The concentrations for the albumin and casein samples were found to be 0.519 and 0.327 mg/mL, respectively based on Warburg-Christian Assay; and 6.5x10-3¬ and 1.9x10-2 mg/mL based on Bradford Assay. In general, the assay indicates that better extraction and purification techniques should be employed. Appropriate quantification techniques should also be used to obtain more accurate results.
Discussion of Data and Results
Proteins are a class of nitrogen-containing organic compounds considered as one of the basic functional units essential to life. Among its many roles include the transport of neutral molecules, ions and electrons such as hemoglobin that transports oxygen; the formation of biological materials such as muscle, hair and bone; or the regulation of activity by binding to other proteins. In this experiment, one of the objectives is to isolate various proteins from known rich sources. The experiment involved the extraction of invertase from baker’s yeast, albumin from fresh egg white, and casein from milk. Spectrophotometric methods were then applied in the characterization and quantification of casein and albumin.
Invertase splits sucrose into glucose and fructose (invert syrup) and can be applied to improve the shelf life of confections. Albumin (ovalbumin) is a globular glycoprotein which is the major component of egg white. It has an isoelectric point of 4.6. Casein is the major
Abstract
Different techniques and principles for protein extraction and characterization were demonstrated in this experiment. Various proteins were extracted from different sources: 1.67 g yeast invertase, 1.03 g egg white albumin, and 5.15 g of milk casein. Activity assay for invertase was performed using Benedict’s test and the enzymes inverting action on sucrose was confirmed. Warburg-Christian Method and Bradford Assay were also employed to determine the protein concentration in the albumin and the casein samples. The concentrations for the albumin and casein samples were found to be 0.519 and 0.327 mg/mL, respectively based on Warburg-Christian Assay; and 6.5x10-3¬ and 1.9x10-2 mg/mL based on Bradford Assay. In general, the assay indicates that better extraction and purification techniques should be employed. Appropriate quantification techniques should also be used to obtain more accurate results.
Discussion of Data and Results
Proteins are a class of nitrogen-containing organic compounds considered as one of the basic functional units essential to life. Among its many roles include the transport of neutral molecules, ions and electrons such as hemoglobin that transports oxygen; the formation of biological materials such as muscle, hair and bone; or the regulation of activity by binding to other proteins. In this experiment, one of the objectives is to isolate various proteins from known rich sources. The experiment involved the extraction of invertase from baker’s yeast, albumin from fresh egg white, and casein from milk. Spectrophotometric methods were then applied in the characterization and quantification of casein and albumin.
Invertase splits sucrose into glucose and fructose (invert syrup) and can be applied to improve the shelf life of confections. Albumin (ovalbumin) is a globular glycoprotein which is the major component of egg white. It has an isoelectric point of 4.6. Casein is the major
References: [1] Biochemistry Academic Group. Biochemistry Laboratory Manual 2007 Ed. Institute of Chemistry, University of the Philippines, Diliman, Quezon City. 2007. pp. 10-15. [2] Boyer, R. F. Modern Experimental Biochemistry 3rd Ed. Addison Wesley Longman, Inc., USA. 2000. pp. 43-44. [3]Boyer, R.F., Concepts in Biochemistry. USA: Brooks/Cole, 1999 [4]Copeland, R.A