Simulating the self-association of caseins

Abstract

A 2-D lattice Monte Carlo model is used to simulate the self-association behaviour of block copolymers with a block size and distribution that models the structure of the four types of milk casein. All the model casein molecules form micelles above a certain chain density (the critical micelle concentration, CMC). The different model casein molecules are shown to form micelles with different morphologies at different attractive hydrophobic block interactions, and these morphologies are consistent with the morphologies that have been observed or have been hypothesized for those natural caseins. Model α s1-casein forms linear micelles where the hydrophobic block attraction is weak and flower-like circular micelles with a dense core at stronger attractions. At high chain densities worm-like micelle solutions are formed. α s2-Casein forms small linear micelles at weak attractions, and dense core micelles at high attractions. β-Casein forms dense core, circular and elongated micelles at relatively strong attractions. It too forms a worm-like micellar solution at higher chain densities. At very high chain densities (84%) the conformations may show some evidence of ordered mesophase formation, as has been observed in previous block copolymer simulations.