Tags: Enzyme.
Thyroid peroxidase or thyroperoxidase (TPO) is an enzyme expressed mainly in the thyroid that liberates iodine for addition onto tyrosine residues on thyroglobulin for the production of thyroxine (T4) or triiodothyronine (T3) the thyroid hormones. In humans thyroperoxidase is encoded by the TPO gene.