The effect of dephosphorylation on the properties of αS1-casein enriched protein
Xiaoli Sun, Skelte G. Anema, Juliet A. Gerrard
Abstract
α S1 -Casein was dephosphorylated using alkaline phosphatase without the interference from proteolysis . The progressive dephosphorylation was monitored by alkaline urea polyacrylamide gel electrophoresis and mass spectrometry techniques. Little change was observed in the SDS-polyacrylamide gel patterns for the native and dephosphorylated α S1 -casein. Dephosphorylation modified the zeta-potential of the α S1 -casein, shifting the pH versus zeta potential curves to higher pH as dephosphorylation increased. The isoelectric pH of the dephosphorylated α S1 -casein increased by about 0.55 pH units when compared with the native protein. Dephosphorylation increased the surface hydrophobicity of α S1 -casein and a negative linear correlation was observed between the surface hydrophobicity and the isoelectric pH of α S1 -casein. Dephosphorylation did not affect the secondary structure of the α S1 -casein.