β-Lactoglobulin B from bovine milk

β-Lactoglobulin B (β-LG B), a isoform of β-Lactoglobulin, is a small protein of 162 amino acids with a molecular mass of 18.2 kDa and optimum pH of 5.2. It is present in high level in casein and is relatively low in raw bovine milk. β-LG has 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.

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 known as BLG A and BLG B.

β-Lactoglobulin B from bovine milk has been used as:

• a protein standard in SDS-polyacrylamide electrophoresis for quantification of milk protein fractions
• in the calibration of reversed phase- high-performance liquid chromatography (HPLC) for caseins quantification
• for immobilization on the biosensor surface and a calibration standards in biosensor assay

β-Lactoglobulin was used in the identification of the genetic variants of κ-casein in milk by isoelectric focusing electrophoresis.

β-Lactoglobulin B (β-LG B) show less inhibitory effect on the Staphylaococcus sp compared to β-LG A.