Protein Hydrolysis and Characterization
Niez, Robert Francis,
*Orbin, Alfonso Ricardo*
Parro, Athena Emmanuelle
Department of Biological Sciences, University of Santo Tomas, Manila, Philippines
Hydrolyzed Protein is protein that has been hydrolyzed or broken down into its component amino acids. While there are many means of achieving this, two of the most common are prolonged boiling in a strong acid (acid-HVP) or strong base or using an enzyme such as the pancreatic protease enzyme to stimulate the naturally-occurring hydrolytic process. A series of tests were performed and yielded positive results for each of the protein hydrolysis. •
Proteins, from the Greek proteios, meaning first, are a class of organic compounds which are present in and vital to every living cell. In the form of skin, hair, callus, cartilage, muscles, tendons and ligaments, proteins hold together, protect, and provide structure to the body of a multicelled organism. In the form of enzymes, hormones, antibodies, and globulins, they catalyze, regulate, and protect the body chemistry. In the form of hemoglobin, myoglobin and various lipoproteins, they affect the transport of oxygen and other substances within an organism. The total protein component of milk is composed of numerous specific proteins. The primary group of milk proteins are the caseins. There are 3 or 4 caseins in the milk of most species; the different caseins are distinct molecules but are similar in structure. All other proteins found in milk are grouped together under the name of whey proteins. The major whey proteins in cow milk are beta-lactoglobulin and alpha-lactalbumin. The major milk proteins, including the caseins, ß-lactoglobulin and a-lactalbumin, are synthesized in the mammary epithelial cells and are only produced by the mammary gland. The immunoglobulin and serum albumin in milk are not synthesized by the epithelial cells. Instead, they are absorbed from the blood (both serum albumin and the immunoglobulins). An exception to this is that a limited amount of immunoglobulin is synthesized by lymphocytes which reside in the mammary tissue (called plasma cells). These latter cells provide the mammary gland with local immunity. Caseins have an appropriate amino acid composition that is important for growth and development of the nursing young. This high quality protein in cow milk is one of the key reasons why milk is such an important human food. Caseins are highly digestible in the intestine and are a high quality source of amino acids. Most whey proteins are relatively less digestible in the intestine, although all of them are digested to some degree. When substantial whey protein is not digested fully in the intestine, some of the intact protein may stimulate a localized intestinal or a systemic immune response. This is sometimes referred to as milk protein allergy and is most often thought to be caused by ß-lactoglobulin. Milk protein allergy is only one type of food protein allergy. Caseins are composed of several similar proteins which form a multi-molecular, granular structure called a casein micelle. In addition to casein molecules, the casein micelle contains water and salts (mainly calcium and phosphorous). Some enzymes are associated with casein micelles, too. The micellar structure of casein in milk is an important part of the mode of digestion of milk in the stomach and intestine, the basis for many of the milk products industries (such as the cheese industry), and the basis for our ability to easily separate some proteins and other components from cow milk. Casein is one of the most abundant organic components of milk, in addition to the lactose and milk fat. Individual molecules of casein alone are not very soluble in the aqueous environment of milk. However, the casein micelle granules are maintained as a colloidal suspension in milk. If the micellar structure is disturbed, the micelles may come...
References: Voet D, Voet JG. (2004). Biochemistry Vol 1 3rd ed. Wiley
Van Holde KE, Mathews CK. (1996). Biochemistry. Menlo Park, Calif: Benjamin/Cummings Pub. Co., Inc.
Murray RF, Harper HW, Granner DK, Mayes PA, Rodwell VW. (2006). Harper 's Illustrated Biochemistry.
Jones, Alicia Noelle (2002). "Density of Milk". The Physics Factbook. Greenwood, Norman N.; Earnshaw, A. (1997), Chemistry of the Elements (2nd ed.)
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