Kinetics of refolding of completely reduced human-serum albumin. Regain of immunochemical reactivity.

The kinetics of refolding of completely reduced human serum albumin has been studied by various methods including immunological techniques. The decrease in thiol content is very rapid in the beginning of the reoxidation process and rather slow in the later stages. Polyacrylamide gel electrophoresis studies show that, in the earlier stages of refolding, the main part of the albumin is present as various oligomers and that a slow conversion to monomer occurs as reoxidation proceeds. Rocket immunoelectrophoresis shows that the completely reduced protein is devoid of native albumin antigenic determinants but that a rapid regain of immunoprecipitability is obtained upon reoxidation. A new 'consumption' rocket immunoelectrophoretic method has been used to estimate the total regain of antigenicity. The data obtained indicate that there is a preferential rapid folding to native structure in certain parts of the molecule but that areas with wrong or incomplete foldings exist a considerable time after the inital refolding period.