Heat Denaturation of Bovine β-Lactoglobulins and Relevance of Disulfide Aggregation

Abstract

The primary and secondary stages of the heat denaturation of bovine fl-laetoglobulin A have been examined using starch gel electrophoresis and sedimentation velocity techniques. The primary reaction results in the formation of a series of molecular aggregates through the establishment of intermoleeular disulfide bonds. A much heavier component is formed during the secondary reaction, but disulfide bonds are not involved in its formation. The results of turbidity experiments indicated that the susceptibility of the genetic variants of fl-lactogIobulin to heat denaturation is in the order fi--C > fi--B > B--A. Tbe relative importance of the fornmtion of disulfide bonds during the aggregation of each variant is discussed. A mechanism describing the behavior during heat treatment is presented.