Nm. Kinghorn et al., QUANTIFICATION OF THE MAJOR BOVINE WHEY PROTEINS USING CAPILLARY ZONEELECTROPHORESIS, Journal of chromatography, 723(2), 1996, pp. 371-379
Citations number
14
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
Bovine whey comprises four major protein groups [alpha-lactalbumin, be
ta-lactoglobulin variants A and B, bovine serum albumin and immunoglob
ulin (specifically IgG)] which have a diverse range of molecular masse
s, pI values, number of phenotypic variants and subunit compositions.
The development of a capillary zone electrophoresis method to separate
these whey proteins is described. Initially separation of the individ
ual whey proteins was evaluated using a number of different buffer sys
tems with pK(a) values above pH 7. At buffer pH values greater than 7,
protein-capillary wall interactions were minimized as the majority of
the whey proteins had a net negative charge because their pI values a
re in the range pH 4-6. A wide range of buffer additives (organic modi
fiers and surfactants) were also added to alter the chemistry of the s
eparation, to further block protein-capillary wall interactions and to
thus optimize the resolution of the different protein peaks. A sample
buffer/separation buffer system was developed which eliminated an ini
tial solvent trough that coincided with the IgG peak. This made it pos
sible to quantify the IgG protein. Optimum resolution and analysis tim
e (10 min) for the four whey proteins was achieved with a sample buffe
r consisting of 10 mM phosphate, pH 7.4 and a separation buffer consis
ting of 150 mM sodium berate, pH 8.5 containing 0.05% Tween 20. This m
ethod was successfully used to separate a mixture of commercially puri
fied whey proteins and to separate and quantitate the individual whey
proteins in an acid whey sample.