What is "bilin"

Bilin \Bi"lin\, n. [Cf. F. biline, from L. bilis bile.] (Physiol. Chem.) A name applied to the amorphous or crystalline mass obtained from bile by the action of alcohol and ether. It is composed of a mixture of the sodium salts of the bile acids.

n. (context biochemistry English) Any of various biological pigments formed in many organisms as a metabolic product of certain porphyrins.

Bilin may refer to:

• Bilin, Mon State, a town in Mon State in Myanmar
• Bilin (biochemistry), a type of biological pigment with a tetrapyrrole structure, for example found in bile
• Bil'in, a Palestinian village in the West Bank
• The Bilen people, an ethnic group which mainly inhabits Eritrea and speaks the Blin language
• The German name for the Czech town of Bílina

Bilins, bilanes or bile pigments are biological pigments formed in many organisms as a metabolic product of certain porphyrins. Bilin (also called bilichrome) was named as a bile pigment of mammals, but can also be found in lower vertebrates, invertebrates, as well as red algae, green plants and cyanobacteria. Bilins can range in color from red, orange, yellow or brown to blue or green.

In chemical terms, bilins are linear arrangements of four pyrrole rings ( tetrapyrroles). In human metabolism, bilirubin is a breakdown product of heme. Hydroxymethyl bilane is a major anabolic product, from the biosynthetic reaction of porphobilinogen (PBG) and uroporphyrinogen I synthase (known as porphobilinogen deaminase).

Examples of bilins are found in animals, and phycocyanobilin, the chromophore of the photosynthetic pigment phycocyanin in algae and plants. In plants, bilins also serve as the photopigments of the photoreceptor protein phytochrome. An example of an invertebrate bilin is micromatabilin, which is responsible for the green color of the Green Huntsman Spider, Micrommata virescens.