Deiodases
Synonym(s)
DefinitionThis section has been translated automatically.
Deiodases are selenoenzymes that activate or inactivate thyroid hormones such as iodothyronines as well as thyronamines and iodothyroacetates by stereospecific deiodination.
A distinction is made between 3 deiodases:
- Type I deiodase (DIO1)
- Type II deiodase (DIO2)
- Type III deiodase (DIO3).
All 3 deiodinases are able to remove iodine atoms from thyroid hormones, thyronamines and iodothyroacetates.
General informationThis section has been translated automatically.
The iodine atoms on the inner ring of iodothyronines are located at the 3- and 5-position, while the iodine atoms on the outer ring are called 3'- and 5'-iodine atoms. The removal of iodine atoms from the inner ring deactivates thyroid hormones.
DIO1 can catalyse both 5'-deiodination and 5-deiodination. DIO2 is a pure 5'-deiodase and can thus activate thyroxine to triiodothyronine, the active thyroid hormone. DIO3 is a 5-deiodase that inactivates thyroxine and triiodothyronine.
LiteratureThis section has been translated automatically.
- Marsili A et al (2011) Physiological role and regulation of iodothyronine deiodinases: a 2011 update-. J Endocrinol Invest. 2011 May; 34: 395-407.