Nomenclature of the Proteins of Cow's Milk: Fourth Revision

Abstract

This report reviews the nomenclature of the milk proteins of cow's milk in light of more recent advances in our knowledge. With the establishment of the primary structures of a number of these proteins, we now have a definite identification of &s 1-, K-, 13-, and the T-caseins as well as t3-1actoglobulin and a-lactalbumin. On the basis of new information on their primary structures and relationship to fl-casein polymorphs, changes in nomenclature have been recommended for proteins of the T-casein fraction. Although the primary structure serves as the unambiguous definition of proteins for which it is known, a more practical identification is necessary. We recommend that their behavior in gel electrophoresis under suitable conditions be employed for this purpose for all of the "major" milk proteins of raw skim milk except the immunoglobulins where, because of their heterogeneity and molecular genetics, physical parameters are less useful and their identification must be based upon antigenic determinants and their homol-Received January 22, 1976. Report of Committee on the Nomenclature and Methodology of Milk Proteins of the Dairy Foods Research Section, Dairy Foods Division, American Dairy Science Association. ogy with their human counterparts. More work is needed and, with the accumulation of more information, additional changes in nomenclature can be expected for such proteins as the minor components of a s-and K-caseins, &-lactalbumin, and the proteose-peptone fraction as well as further confirmation of the presence of immunoglobulins IgE and additional IgG subclasses. Additional components and genetic variants also can be expected.