The effect of dephosphorylation on the properties of αS1-casein enriched protein

αS1-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 αS1-casein. Dephosphorylation modified the zeta-potential of the αS1-casein, shifting the pH versus zeta potential curves to higher pH as dephosphorylation increased. The isoelectric pH of the dephosphorylated αS1-casein increased by about 0.55 pH units when compared with the native protein. Dephosphorylation increased the surface hydrophobicity of αS1-casein and a negative linear correlation was observed between the surface hydrophobicity and the isoelectric pH of αS1-casein. Dephosphorylation did not affect the secondary structure of the αS1-casein.