Kinetics of formation of hydrophobic regions during refolding of bovine serum albumin.

The rate of formation of hydrophobic regions during refolding of bovine serum albumin was studied using 1-anilinonaphthalene-8-sulfonate as the hydrophobic fluorescent probe. The refolding of serum albumin exhibited a sigmoidal behavior. The exhibition of a lag phase followed by a faster kinetic phase suggested that the refolding is a cooperative, sequential process. Refolding under reducing conditions almost completely inhibited the regeneration of hydrophobic binding regions, suggesting that the formation of disulfide bonds plays an important role in the refolding of serum albumin. The rate and the extent of refolding was apparently maximum at about 20 degrees; at 37 degrees the extent of refolding was very low compared to that at the other temperatures studied. Based on the results, the mechanism of albumin refolding is interpreted in terms of domain structures and interdomain interactions.