Beta-lactoglobulin
Beta-lactoglobulin | |||||||
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UniProt P02754 | | ||||||
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β-Lactoglobulin (BLG) is the major
Function
The major protein in whey is β-lactoglobulin, followed by
Structure
Several variants have been identified, the main ones in the cow being labelled A and B. Because of its abundance and ease of purification, it has been subjected to a wide range of biophysical studies. Its structure has been determined several times by
Bovine β-lactoglobulin is a relatively small protein of 162
β-Lactoglobulin solutions form gels in various conditions, when the native structure is sufficiently destabilised to allow aggregation.[17] Under prolonged heating at low pH and low ionic strength, a transparent `fine-stranded' gel is formed, in which the protein molecules assemble into long stiff fibres.
β-Lactoglobulin is the main component of milk skin, coagulating and denaturing when the milk boils. Once denatured, the β-Lactoglobulin forms a thin gelatinous film on the surface of the milk.
Folding intermediates for this protein can be studied using light spectroscopy and denaturant. Such experiments show an unusual but important intermediate composed purely of alpha helices, despite the fact that the native structure is beta sheet. Evolution has probably selected for the helical intermediate to avoid aggregation during the folding process.[18]
Clinical significance
As milk is a known allergen,
Laboratory polymerization of β-lactoglobulin by microbial transglutaminase reduces its allergenicity in children and adults with an IgE-mediated cow’s milk allergy.[23]
Cows breeding
In 2018 it was announced that genetically modified cows were grown.[6] The cows had their β-Lactoglobulin producing genes removed by a zygote-mediated deletion process.[6]
See also
- Caseine
References
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- ^ a b listed in Annex IIIa of Directive 2000/13/EC
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