Determination of ovine casein heterogeneity using gel electrophoresis and immunochemical techniques

Discontinuous PAGE at alkaline and acid pH, polyacrylamide gel isoelectric focusing, two dimensional electrophoresis and immunoblotting have been used to study the heterogeneity of sheep caseins. Three main phenotypes were selected either because of mobility at alkaline and acid pH of the individual alpha s components or because of their relative intensity. On electrophoresis at alkaline pH, one phenotype showed two distinct bands of lower electrophoretic mobility than beta 1- and beta 2-caseins. A detailed study of these components using immunospecific detection with beta-casein antiserum showed that these minor components of ovine casein may have a polypeptide chain similar to that of beta 1- and beta 2-caseins. Complete electrophoretic patterns of the casein components in some individual milks are also presented.