Internal Structure of Casein Micelles from Bovine Milk

Abstract

The internal structure of casein micelles from bovine milk has been reinvestigated. Observations from electron microscopy, X-ray diffraction, and enzymatic digestion of the micelles followed by centrifugation suggested that electron-dense particles in the micelles are probably granules of colloidal calcium phosphate and not protein aggregates. These granules are embedded in a surrounding matrix of caseins to form the micelle. The foci of formation of the calcium phosphate granules may be either the ester phosphate groups or the ɛ-amino groups of lysine. © 1966, American Dairy Science Association. All rights reserved.