The Amino Acid Composition of the Fat-Globule Membrane Protein of Milk

Summary Sixteen amino acids have been determined microbiologically on two different samples of the fat-globule membrane protein substance isolated from washed cream. Close agreement in amino acid composition was observed between the two preparations. Lysine and arginine showed the widest variation. The amino acid composition of the membrane proteins was compared with that of casein, lactalbumin and lactoglobulin. Little similarity was noted between the membrane protein and the major milk proteins which suggests that the former was a unique protein(s) and did not find its origin in either casein, lactalbumin or lactoglobulin.