Milk Proteins | Casein, Micellar Structure

The physicochemical properties of the casein proteins are summarized insofar as these provide the basis for the dual-binding model of casein micelle assembly and structure. The dual-binding model exploits the amphiphilic nature of the caseins, allowing interprotein interactions between hydrophobic regions of the proteins, as well as bridging links across calcium phosphate nanoclusters bound to the phosphoseryl clusters of the individual casein proteins. In this way, a three-dimensional structure is built up, with growth limited by the inability of the κ-casein to continue the polymerization pathways. As outlined here, the dual-binding model readily provides mechanistic explanations and understanding of all known functional behavior of casein micelles. Earlier models of the casein micelle are reviewed next to demonstrate how the dual-binding model overcomes their shortcomings and deficiencies.