Corrin
From Wikipedia, the free encyclopedia
- This article is about the chemical macrocycle. For the world of the same name in Frank Herbert's Dune, see Corrin (Dune).
A corrin is a macrocycle related to the porphyrin ring in hemoglobin, consisting of 4 pyrrole subunits, joined on opposite sides by a C-CH3 methylene link, on one side by a C-H methylene link, and with the two of the pyrroles joined directly. Compared to a porphyrin, it is missing a bridging methylene group between a pair of pyrroles. This ring is central to the cobalt containing vitamin, vitamin B12, or cobalamin. Corrins have properties related to porphyrins, but:
- They are more flexible than porphyrins.
- They are not as flat as porphyrins.
- Because of the loss of the bridging methylene, they do not have a full conjugated character around the entire ring. Instead, the ring has a kind of "3/4" conjugation.
The related corroles are fully aromatic.
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| Major Families of Biochemicals | ||
| Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides | ||
| Analogues of nucleic acids: | Types of Tetrapyrroles | Analogues of nucleic acids: |
| Bilanes: | Bilirubin | Biliverdin | Urobilinogen | Urobilin | |
|---|---|---|
| Chlorophylls: | Protochlorophyllide | Chlorophyllide | |
| Corrinoids: | Cyanocobalamin | |
| Phycobilins: | Phycoerythrobilin | Phycocyanobilin | Phycourobilin | Phycoviolobilin | |
| Porphyrins: | Coproporphyrinogen | Protoporphyrin | Uroporphyrinogen | |
