PHOSPHORYLATION OF BETA-LACTOGLOBULIN USING AMINO-ACIDS AS THE SOLE BASE AND NUCLEOPHILE OF THE REACTION

beta-Lactoglobulin was phosphorylated with 20, 40, and 80 mol of POCl3 /mol protein in the presence of 4, 5, and 6 molar excess of basic amin o acid per mol POCl3. Maximal phosphorylation yields of 5 and 3 mol P/ mol protein were achieved when the highest stoichiometries of POCl3/ar ginine and lysine were used. Proportional high amounts of basic amino acids were also grafted to the protein molecule during its phosphoryla tion through the phosphoamide bond. Modified proteins displayed increa sed negative charges and reduced isoelectric points and were monomeric . The phosphorylated and phosphoamidated beta-lactoglobulin showed imp roved functional properties.