Types
In most vertebrates, there are three types of enzymes that can deiodinate thyroid hormones:
| Type | Location | Function |
| type I (DI) | is commonly found in the liver and kidney | DI can deiodinate both rings |
| type II deiodinase (DII) | is found in the heart, skeletal muscle, CNS, fat, thyroid, and pituitary | DII can only deiodinate the outer ring of the prohormone thyroxine and is the major activating enzyme (the already inactive reverse triiodothyronine is also degraded further by DII) |
| type III deiodinase (DIII) | found in the fetal tissue and the placenta | DIII can only deiodinate the inner ring of thyroxine or triiodothyronine and is the major inactivating enzyme |
The following is a list of the three human iodothyronine deiodinases:
|
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Read more about this topic: Iodothyronine Deiodinase
Famous quotes containing the word types:
“The wider the range of possibilities we offer children, the more intense will be their motivations and the richer their experiences. We must widen the range of topics and goals, the types of situations we offer and their degree of structure, the kinds and combinations of resources and materials, and the possible interactions with things, peers, and adults.”
—Loris Malaguzzi (1920–1994)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)
“Our children evaluate themselves based on the opinions we have of them. When we use harsh words, biting comments, and a sarcastic tone of voice, we plant the seeds of self-doubt in their developing minds.... Children who receive a steady diet of these types of messages end up feeling powerless, inadequate, and unimportant. They start to believe that they are bad, and that they can never do enough.”
—Stephanie Martson (20th century)