Capillary electrophoresis of caseino-peptides: influence of applied voltage and column temperature

The peptides formed upon action of purified cardoon rennet on the Ala sub(189)-Phe sub(190)-Leu sub(191)-Leu sub(192)-Tyr sub(1)93 beta -casein fragment were separated by capillary electrophoresis in an uncoated fused silica capillary. There was a linear correlation between electrophoretic mobility and Z/M super(2/3) (Z, net charge; M, molecular mass) under all experimental conditions tested; under the optimal condicitions, 25 kV and 40 degree C, the correlation coefficient was 0.994. The reported method is fast (migration times less than 7 min) and may be used to study the action of aspartic proteinases on the C-terminal domain of beta -casein and thus to help elucidate their effect on cheese quality.