CONFORMATIONAL-CHANGES OF PEROXIDASE AND ALBUMIN IN SOLUTIONS OF PROPYLTHIOURACIL

Conformational changes of peroxidase and albumin in buffered solutions of propylthiouracil, an antithyroid drug, were evaluated by dilatometry and viscometry, showing that the structural alteration of peroxidase is related to the decoupling of the reactions which it catalyses. Thus, propylthiouracil probably inactivates the peroxidase by altering its structure. Equilibrium dialysis showed that albumin is the principle propylthiouracil-transporting protein in human serum. Propylthiouracil induces a conformational change in albumin when 1 mole of drug per mole of protein is bound, a structural alteration that can change the binding capability of other ligands. © 1990.