SOME MINOR COMPONENTS OF CASEIN AND OTHER PHOSPHOPROTEINS IN MILK . A REVIEW

γ-Casein and other minor proteins, tentatively designated TS-, R-, and S-casein, have been identified in unfractionated casein by disc gel electrophoresis. γ-Casein is polymorphic and like β-casein it shows three variants of the A type and one B type. So far, no γ-C casein has been observed. The A2 and B polymorphs of γ- and β-casein show the same amino acid substitutions. The R-casein is found in the A samples; the S-casein is associated with caseins typed B with respect to γ-, β- casein. TS-Caseins occur in all samples and are polymorphic. This review will also discuss recent data other minor caseins, the components of the proteosepeptone fraction, and the phosphoglycoprotein fraction of whey. © 1969, American Dairy Science Association. All rights reserved.