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 αs-caseins in high purity. Subsequent to chemical fractionation, the αs-caseins were ehromatographed on DEAE-cellulose in the presence of 3.3 m urea. αs-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 κ-casein. Due to the presence of other αs-like caseins in cow's milk, the authors have proposed that the genetic variants of the fraction called αs-casein be termed αs1-A, αs1-B, and αs1-C. Further identification of the αs1-caseins was made by their relative electrophoretic mobilities on starch-gel and polyacrylamide-gel. © 1964, American Dairy Science Association. All rights reserved.