HUMAN ALPHA-S-1-CASEIN LIKE PROTEIN - PURIFICATION AND N-TERMINAL SEQUENCE DETERMINATION

Casein components of human milk are generally reported to belong to th e beta- and chi-groups. In this research human casein fraction was obt ained from pooled mature milk, either by ultracentrifugation or by aci d precipitation. In both cases a minor component with a slightly highe r mobility in SDS-PAGE than beta-casein was identified. The protein wa s purified to homogeneity, the N-terminal sequence of the first 14 ami no acid residues of this new human casein subunit shows a high degree of homology with the alpha s(1)-casein sequences from other species.