Modification of Carboxyl Groups of α_s- and κ-Casein

Abstract

α_s-Casein and κ-casein were modified by esterification of free carboxyl groups using carbodiimide method with glycinemethylester. Effect of the modification on the precipitation of calcium as-caseinate, the formation of α_s-κ-casein complex and the stabilizing activity of κ-casein on α_s-casein have been investigated. The modification of free carboxyl groups of α_s-casein brought about a decrease of calcium sensitivity. The modified κ-casein did not form the complex with α_s-casein. The stabilizing activity of κ-casein on α_s-casein was deteriorated by the modification.