Bovine α-lactalbumin C and αS1-, β- and k-caseins of bali (banteng) cattle, bos (bihos) javanicus

Abstract

An electrophoretic examination is made of milk samples taken from eight Bali (banteng) cattle, Bos (Bibos) javanicus, at Beatrice Hills, Northern Territory, Australia. Starch-gel electrophoresis at pH 8 · 5 (NaOH-H3B03 buffer) and filter-paper electrophoresis at pH 8· 6 (diethylbarbiturate buffer) indicate that all samples contain a new α-lactalbumin variant, designated a-lactalbumin C. The order of mobility for bovine variants is A > B > C. The C variant differs from the common B variant in having one more amide residue (substitution of Asn for Asp or GIn for Glu). © ASEG. Examination of milk samples by urea-starch-gel electrophoresis at alkaline pH indicates that there is a new asrcasein variant, designated αs1-casein EBali;, present in some samples. No new K-casein variant is detected by this method (all samples typing as K-casein B). A new variant of β-casein, designated A4is detected by urea-starch-gel electrophoresis at low pH. The variants of milk proteins observed in this paper and in Bell et al. (1981) are discussed in relation to those of other members of the Bovinae, especially the yak, Bos (Poephagus) grunniens. © 1981 ASEG.