Bovine ß-Lactoglobulin E, F and G of Bali (Banteng) Cattle, Bos (Bihos) Javanicus

Abstract

An electrophoretic examination is made of samples of milk from eight Bali (banteng) cattle, Bos (Bibos) javanicus, in the Northern Territory of Australia. There are two new electrophoretically distinct bovine ft-Iactoglobulins, designated E and F, present in these samples. It is shown by amino acid analysis and tryptic peptide mapping of isolated samples that: (I) both E and F differ from the B variant of domestic cattle (Bos taurus) by + 1 G1y, -1 Glu at residue 157 or 158; and (2) the F variant has the additional charge differences from E and B due to + I Tyr, -1 Asp at residue 129 or 130. It is also shown by studies of peptides produced by the action of Staphylococcus aureus strain V8 protease and by more recent amino acid analyses that (1) the GlyjGlu substitution is at residue 158; (2) there is an additional Bali variant, designated ft-lactoglobulin G, differing from E by + 1 Met, -1 lie at residue 78, but having the same mobility as E; and (3) there is an hitherto undetected neutral residue substitution of + 1 Ser, -1 Pro at position 50 in the F variant. The relation of these variants to other known ft-lactoglobulin variants of the Bos genus is discussed.

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

“…These were similar to those used by Bell et al (1981), with the following additions. Filter-paper electrophoresis of total 'whey' protein was performed according to the method of Aschaffenburg and Drewry (1955).…”

“…No new K-casein variant is detected by this method (all samples typing as K-casein B). A new variant of jJ-casein, designated A4, is 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. …”

“…All skim milk samples of the eight Bali (banteng) cows were examined by the starch-gel electrophoresis procedure for typing f3-lactoglobulin, as described by Bell et al (1981), and showed a single rx-lactalbumin band, moving more slowly than the A and B variants (see Fig. 1 of that paper).…”

“…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.…”

“…In the paper by Bell et al (1981) we have examined samples of milk taken from eight Bali (banteng) cattle, Bos (Bibos) javanicus, at the Beatrice Hills Experiment Station, Northern Territory. It was shown that f)-lactoglobulin is the dominant whey protein present and that it occurs as three new variants, designated f)-lactoglobulin E, F and G. In the course of this work it was noticed that there was a prominent band due to a-lactalbumin, moving more slowly than bovine a-lactalbumin B of Bos taurus or the A variant of Bos indicus.…”