Chemistry of thyroid hormones doesn't make sense?

[sameeralord]

Hello everyone,

This is a DIT molecule.

Now the book says there is a coupling reaction DIT + DIT ----> gives T4 molecule or tyroxine hormone

Now this is how T4 looks like

I don't understand how you can get this when there is a addition reaction between these two. Does coupling mean something else. Thank you

 

[pzona]

Coupling reactions are something entirely different from addition. Here's the basics:

http://en.wikipedia.org/wiki/Coupling_reaction

 

[sameeralord]

Coupling reactions are something entirely different from addition. Here's the basics:

http://en.wikipedia.org/wiki/Coupling_reaction

Thanks Somehow I totally forgot to check what coupling reaction mean, I just took it literally thinking it was an addition reaction.

 

[alxm]

This is almost certainly an enzyme-catalyzed reaction. I'm guessing that by 'coupling reaction' they just mean that it's occurring in a metalloenzyme.

Even without knowing the enzyme in question I'd expect as much, given the nature of the reaction. Substitution on a phenyl ring is not easy, and might even require forming a radical intermediate.

 

[LudusRex]

Hello,

I can understand your confusion about the chemistry behind thyroid hormones. However, the coupling reaction described in your book is a common reaction in organic chemistry called a condensation reaction. In this reaction, two molecules combine to form a larger molecule with the release of a smaller molecule, usually water. This type of reaction is different from addition reactions, where two molecules simply combine without the release of any byproducts.

In the case of thyroid hormones, the two DIT molecules undergo a condensation reaction to form a larger molecule called T4 or thyroxine. This is a key step in the synthesis of thyroid hormones in the body. While it may seem counterintuitive that two molecules can combine to form a larger molecule, this type of reaction is actually quite common in biological systems.

I hope this explanation helps to clarify the chemistry of thyroid hormones for you. If you have any further questions, please don't hesitate to ask. As scientists, it is important for us to constantly question and seek understanding in order to further our knowledge and make new discoveries. Thank you for your curiosity and interest in this topic.

Best,