Genetic Polymorphism in Caseins of Cow's Milk. III. Isolation and Properties of αs1-Caseins A, B, and C

Abstract

A convenient method is described for obtaining the genetic variants of [alpha]s -caseins in high purity. Subsequent to chemical fractionation, the [alpha]s-caseins were chromatographed on DEAE-cellulose in the presence of 3.3 M urea. [alpha]s-A, B and C caseins contain 1.01% phosphorus and 15.10, 15.34, and 15.40% nitrogen, respectively. Each is stabilized against precipitation with Ca++ by [kappa] -casein. Due to the presence of other as-like caseins in cow''s milk, the authors have proposed that the genetic variants of the fraction called as-casein be termed [alpha]s1-A, s1-B, and [alpha]s1-c. Further identification of the s1i-caseins was made by their relative electrophoretic mobilites on starch-gel and polyacrylamide-gel.