Chemistry of the caseins

The caseins are the predominant class of proteins in the milk of all common dairying species. This class represents four phosphoproteins, i.e. α_s1-, α_s2-, β- and κ-casein. Their amino acid sequence combined with post-translational phosphorylation and, in the case of κ-casein, glycosylation yields a unique class of rheomorphic proteins which contain comparatively little secondary and tertiary structure and associate to form crucial building blocks for casein micelles. This chapter discusses the chemistry and biochemistry of caseins, with particular attention to primary and higher order structures, genetic variation, post-translational modification, disulphide interactions, self-association and interactions with minerals.