Thyroid peroxidase
Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine residues on thyroglobulin for the production of thyroxine ( T4 ) or triiodothyronine ( T3 ) , the thyroid hormones . 
<triplet> triiodothyronine <subj> thyroxine <obj> instance of <subj> thyroid hormones <obj> instance of