Dephosphorization of Casein by Heat Treatment. I. In Caseinate Solutions

Heat treatment of 3% sodium a-, ~-, and unfractionated caseinate solutions at 110 to 140 C progressively released the casein phosphate as inorganic orthophosphate. Under the conditions studied, all of the samples conformed to first-order kinetics. The energy of activation E was calculated to be 28-29 kcal per mole of phosphate, the same as for the dephosphorization of 0-serine phosphate. Calculations of the entropy change AS ~ for the activated complexes of casein phosphate and O-serine phosphate gave a value of --5 cal per mole per degree. Structurally, the molecules are considered to have been altered very slightly from the original. The data indicate that the hydrolysis of phosphorus from casein proceeds through an oxygen-phosphorus fission.