The Interaction of Cosolvents, Proteolytic Enzymes and Selective Metal Ions with alpha-Casein - The Structure - Stability Relationship

Srinivas, Sistla (2006) The Interaction of Cosolvents, Proteolytic Enzymes and Selective Metal Ions with alpha-Casein - The Structure - Stability Relationship. PhD thesis, University of Mysore.

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Abstract

Caseins are the predominant milk proteins present in all mammalian species. They comprise approximately 80% of the total protein content in milk. They constitute a heterogeneous group of phospho-proteins present as stable calcium phosphate complexes termed micelles. The biological functions of the caseins are to provide the progeny with a source of phosphate and calcium for the mineralization process of calcified tissues, amino acids and biologically important peptides. The principal proteins in this group are αS1-casein, αS2-casein, β-casein, and κ-casein classified according to the homology of their primary structures. In the present study, effect of cosolvents, proteolytic enzymes and metal ions on α-casein structure and function and stability was studied. Bovine milk α-casein constitutes 65% of total casein. α-Casein contains a mixture of αS1 casein and αS2 casein in the ratio of 4:1. This group consists of closely related phospho-proteins, with a molecular weight of 27,300 Da. α-Casein is easily degradable protein due to its random coil structure. α-Casein are grouped under intrinsically unstructured proteins. The aperoidicity of the protein is due to the presence of 8.5% proline residues uniformly distributed in the polypeptide chain. The flexibility and randomness in the structure of α-casein, is a reason for the release of many potential peptides with various biological activities, when hydrolyzed by proteolytic enzymes. The effect of proteolytic enzymes on the release of biologically activity peptides was studied. The part of the study is to screen for the novel multifunctional peptides from α-casein, which can be incorporated into nutraceutical and functional foods. The structure-function studies of these peptides will reveal their mechanism of biological activity and mode of action. The interaction of cosolvents with proteins and peptides will to stabilize them for their optimum utilization. Effect of different cosolvents on the structural stability is investigated in order to understand the basic mechanism of stabilization of α-casein, as a result of microenvironment changes brought about by these cosolvents. Effect of different cosolvents on the functional stability is investigated to optimize their performance at extremes of temperatures. The biological activity of peptides was also studied in presence of various cosolvents for their functional optimization. The present study is focused to address the question regarding the structure-function relationships of α-casein in presence of metal ions like zinc and lead.

Item Type:	Thesis (PhD)
Uncontrolled Keywords:	α-casein Caseins proteolytic enzymes bioactive peptides metal ions
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 29 Protein Chemistry 600 Technology > 08 Food technology > 27 Dairy products
Divisions:	Protein Chemistry and Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	24 Dec 2007 04:47
Last Modified:	28 Dec 2011 09:32
URI:	http://ir.cftri.res.in/id/eprint/1600

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