Reoxydation der Disulfidbrücken des menschlichen Choriongonadotropins (HCG)

After alkylation of human chorionic gonadotropin (HCG) with iodoacetate in 4 M guanidine-HCl and in 8 M urea, 1.6 and 0.6 mole equivalents of carboxymethylcysteine were found, respectively. The biological activity of these preparations was 25% of the original specific activity.Slow reoxidation of completely reduced HCG with oxygen yields products having 15 - 25% of the original specific activity, while fast reoxidation results in complete loss of biological activity and immunological specificity.Immunological specificity and 25% of the original biological activity can be recovered if the disulfide bonds of the inactive sample are reequilibrated in the presence of β-mercaptoethanol.