Description_x000D_ General description_x000D_ Milk from dairy cows contains the protein β-lactoglobulin (BLG). It naturally occurs in a number of genetic variants, and the most prevalent bovine variants are BLG A and BLG B._x000D_ Application_x000D_ β-Lactoglobulin was used in the identification of the genetic variants of κ-casein in milk by isoelectric focusing._x000D_ Biochem/physiol Actions_x000D_ A member of the lipocalin family, βLg is a small protein of 162 amino acids with a molecular mass of ∼18,400 Da. It has an eight-stranded β-barrel (strands A-H) succeeded by a three-turn α-helix and a final β-strand (strand I) that forms part of the dimerization interface.