Skip to main content
Article
Review of the chemistry of αS2-casein and the generation of a homologous molecular model to explain its properties
Journal of Dairy Science
  • H. M. Farrell, USDA ARS Eastern Regional Research Center
  • E. L. Malin, USDA ARS Eastern Regional Research Center
  • E. M. Brown, USDA ARS Eastern Regional Research Center
  • A. Mora-Gutierrez, Prairie View A&M University
Document Type
Article
Abstract

αS2-Casein (αS2-CN) comprises up to 10% of the casein fraction in bovine milk. The role of αS2-CN in casein micelles has not been studied in detail in part because of a lack of structural information on the molecule. Interest in the utilization of this molecule in dairy products and nutrition has been renewed by work in 3 areas: biological activity via potentially biologically active peptides, functionality in cheeses and products, and nutrition in terms of calcium uptake. To help clarify the behavior of αS2-CN in its structure-function relationships in milk and its possible applications in dairy products, this paper reviews the chemistry of the protein and presents a working 3-dimensional molecular model for this casein. The model was produced by threading the backbone sequence of the protein onto a homologous protein: chloride intracellular channel protein-4. Overall, the model is in good agreement with experimental data for the protein, although the amount of helix may be over-predicted. The model, however, offers a unique view of the highly positive C-terminal portion of the molecule as a surface-accessible area. This region may be the site for interactions with κ-carrageenan, phosphate, and other anions. In addition, most of the physiologically active peptides isolated from αS2-CN occur in this region. This structure should be viewed as a working model that can be changed as more precise experimental data are obtained. © American Dairy Science Association, 2009.

DOI
10.3168/jds.2008-1711
Publication Date
1-1-2009
Citation Information
H. M. Farrell, E. L. Malin, E. M. Brown and A. Mora-Gutierrez. "Review of the chemistry of αS2-casein and the generation of a homologous molecular model to explain its properties" Journal of Dairy Science Vol. 92 Iss. 4 (2009) p. 1338 - 1353 ISSN: 00220302
Available at: http://works.bepress.com/adela-mora-gutierrez/5/