<prompt> Mechanism of action of propylthiouracil:inhibition of organification of iodineinhibition of oxidationinhibition of couplingall of the above  <response>: Ans. D. All of the aboveThyroid peroxidase enzyme is responsible for oxidation, organification and coupling of thyroid hormone. Thus, propylthiouracil is the inhibitor of thyroid peroxidase enzyme and modulate all the functions. 