Bile pigments
When bile pigments linear be Tetrapyrroles referred that as products in the degradation of porphyrins , particularly the heme stake of hemoglobin , arise. When the porphyrins are broken down, the α-methine bridge between rings A and B of the protoheme is oxidatively cleaved. The cleavage takes place with the help of microsomal hydrolases , which absolutely require the NADPH ferrihemoprotein reductase EC 1.6.2.4 .
The breakdown of hemoglobin takes place in the liver , the pigments are stored in the bile and excreted with the faeces and urine , which creates their typical colors; they are thus also to the Urochromen ( urine pigments ) and Koprochromen ( Fäkalpigmente ).
Classification
Based on the basic body of the bile pigments and the methine groups they contain , the group is divided into "Bilane", "Bilene", "Biladiene" and "Bilatriene". In the overview table the bridging methine groups are shown in red ( - = ), terminal methine groups in blue ( - = ):
| Base body | Number Something groups |
colour | Representative | Structural formula |
|---|---|---|---|---|
| Bilan | 0 | colorless |
Mesobilirubinogen "i-Urobilinogen" |
|
| Sterkobilinogen |
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d-urobilinogen "d-mesobilinogen" |
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| Bilen | 1 | yellow to orange | Sterkobilin |
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d-urobilin "d-mesobilin" |
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i-Urobilin "i-Mesobilin" |
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| Biladia | 2 | red | Bilirubin |
|
| Mesobilirubin |
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Phycoerythrobilin, see phycoerythrin |
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| Bilatria | 3 | green to blue | Biliverdin |
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Phycocyanobilin see phycocyanin |
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numbering
The following graphic illustrates the numbering of the four different rings (A – D) and the substitutable positions:
Web links
- Nomenclature of Tetrapyrroles (PDF; 1.4 MB) IUPAC.org