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Reducer driven baric denaturation and oligomerisation of whey proteins
1Institute of Biochemical Physics, Russian Academy of Sciences, Vavilov Str. 28, 117813 GSP-1, Moscow, Russia.
Journal of Biotechnology
|June 27, 2000
Summary
High pressure causes alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) to form disulfide-linked oligomers. This protein oligomerization requires beta-lactoglobulin (BLG) and is initiated by thiol-disulfide exchange.
Area of Science:
- Protein chemistry
- High-pressure science
- Biochemistry
Background:
- Alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) are major whey proteins.
- Understanding protein interactions under stress is crucial for food processing and biotechnology.
Purpose of the Study:
- To investigate the effect of high pressure on ALA/BLG mixtures.
- To determine the conditions favoring protein oligomerization.
Main Methods:
- Gel-permeation chromatography
- Sodium dodecyl sulphate (SDS) gel electrophoresis
- High-pressure treatment (10 kbar/1000 MPa)
Main Results:
- High-molecular protein disulfide oligomers formed when the weight fraction of BLG exceeded 0.2.
- Maximum oligomer yield (80-85%) occurred at BLG fractions >= 0.4.
- Both ALA and BLG were similarly converted into oligomers, indicating intermolecular disulfide bond formation.
Conclusions:
- Protein oligomerization in ALA/BLG mixtures under high pressure is dependent on BLG content.
- Thiol-disulfide exchange, initiated by exposed thiol groups in BLG, drives oligomerization.
- Intermolecular disulfide bond formation is essential for pressure-induced oligomerization.