54385
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 ) , thyroid hormones .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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