Bilin (biochemistry)

As bile pigments linear tetrapyrroles are called, which as products of the degradation of porphyrins, especially the heme portion of hemoglobin arise. The degradation of porphyrins occurs oxidative cleavage of the α - methine bridge between rings A and B of the Protohäms. The cleavage takes place with the help of microsomal hydrolases necessarily the NADPH Ferrihämoprotein reductase EC 1.6.2.4 need.

The degradation of hemoglobin occurs in the liver, the dyes are stored in the bile and excreted in the feces and urine, thereby resulting in their typical colors; they are therefore also to the Urochromen ( urine pigments) and Koprochromen ( Fäkalpigmente ).

Classification

Based on the main body of the bile pigments and the methine groups contained therein, the group in " Bilane ", " Bilene ", " Biladiene " and " Bilatriene " divided. ( - =) In the summary table, the bridge methine each red are shown, terminal methine groups in blue ( - =):

Numbering

The following graphic illustrates the numbering of the four rings (A -D) and the substitutable positions: