Lactalbumin genetic variant

The proteins of milk fall into several classes of polypeptide chains. These have been delineated most completely in bovine milk, and a system of nonmenclature has been developed for them (Chapter 3 Eigel et al. 1984). One group, called caseins, consists of four kinds of polypeptides asr, as2-. and 3-, and k- with some genetic variants, post translational modifications, and products of proteolysis. Almost all of the caseins are associated with calcium and phosphate in micelles 20-300 fim in diameter (see Chapter 9). The other milk proteins, called whey proteins, are a diverse group including /3-lactoglobulin, a-lactalbumin, blood serum albumin, and immunoglobulins (Chapter 3). Almost all... 

The occurrence of genetic variants of bovine a-lactalbumin, reflecting autosomal alleles without dominance, is now well established (Table II). Porcine a-lactalbumin appears to be the only other a-lactalbumin for which similar genetic variation has been established (for references, see Table II, footnote a). 

In addition to comparison of amino acid and nucleotide sequences of a-lactalbumin, and their rates of change as molecular clocks, a considerable amount of comparative information has accumulated on the three-dimensional structure of these proteins their physical properties in soludon effects of amino acid subsdtudons, in both genetic and cloned variants and their funcdons and immunological properties. In assessing this informadon it is important not to lose sight of the known paleontological informadon on the origin and evolution of mammals. 

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