Encyclopedia > Corrin

  Article Content


A corrin is a polyaromatic ring 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 aromatic character around the entire ring. Instead, the ring has a kind of "3/4" aromaticity.

All Wikipedia text is available under the terms of the GNU Free Documentation License

  Search Encyclopedia

Search over one million articles, find something about almost anything!
  Featured Article

... is Lake Winnipesaukee, which covers 72 square miles in the central part of New Hampshire. New Hampshire has the shortest ocean coastline of any state, just 18 miles. ...