Bovine a-Lactalbumin C and aS1-, ß- and ?-Caseins of Bali (Banteng) Cattle, Bos (Bihos) Javanicus

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Abstract
An electrophoretic examination was made of milk samples taken from 8 Bali (banteng) cattle, Bos (Bibos) javanicus, at Beatrice Hills, Northern Territory, Australia. Starch-gel electrophoresis at pH 8.5 (NaOH-H3BO3 buffer) and filter-paper electrophoresis at pH 8.6 (diethylbarbiturate buffer) indicated that all samples contain a new .alpha.-lactalbumin variant, designated .alpha.-lactalbumin C. The order of mobility for bovine variants is A > B > C. The C variant differs from the common B variant in having 1 more amide residue (substitution of Asn for Asp or Gln for Glu). Examination of milk samples by urea-starch-gel electrophoresis at alkaline pH indicated that there is a new .alpha.s1-casein variant, designated .alpha.s1-casein EBali, present in some samples. No new .kappa.-casein variant was detected by this method (all samples typing as .kappa.-casein B). A new variant of .beta.-casein, designated A4, was detected by urea-starch-gel electrophoresis at low pH. The variants of milk proteins observed are discussed in relation to those of other members of the Bovidae, especially the yak, Bos (Poephagus) grunniens.