|Jmol-3D images||Image 1
|Molar mass||237.216 g/mol|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Biopterin refers to a number of pterin coenzymes produced and utilised by many species including humans and animals. Biopterins and similar compounds are also found in some bacteria and fungi. Biopterins act as cofactors for aromatic amino acid hydroxylases, which produce a number of neurotransmitters including dopamine, norepinepherine, epinepherine, and seratonin. They are also required for the production of nitric oxide, which is also used in cell-cell signalling, most notably in regulating blood pressure by dilating blood vessels.
Biopterin synthesis occurs through two principal pathways; the de novo pathway involves three enzymatic steps and proceeds from GTP, while the salvage pathway converts Sepiapterin to biopterin. BH4 is the principal active cofactor, and a recycling pathway converts BH2 to BH4.
The link below shows how biopterin is produced in the body. http://home.sandiego.edu/~cloer/loerlab/biopterin_syn.gif
Another link shown below provides another image, but complete with molecular structures. http://www.pnas.org/content/104/38/15081/F3.expansion.html
The final image in the link below shows biopterin rearranged in three different forms. http://ebm.rsmjournals.com/content/228/11/1291/F2.expansion.html
A number of disorders of biopterin regulation exist.
Single-gene defects affecting the gene GCH1 block the first step in biopterin synthesis, and lead to Dopamine-responsive dystonia, also known as Segawa's syndrome. This is due to the role of BH4 in synthesising neurotransmitters, including Dopamine, and is treated with supplementation with levodopa, which does not require BH4 for conversion to dopamine. GCH1 defects are autosomal dominant, meaning that only one defective gene copy is required for the condition to occur. Mouse gene knockout models that block biopterin synthesis completely die shortly after birth due to their inability to produce catecholamines and neurotransmitters. Biopterin synthesis disorders are also a cause of hyperphenylalaninemia; phenylalanine metabolism requires BH4 as a cofactor.
WiseGeek. (2012). What is biopterin?. Retrieved from http://www.wisegeek.com/what-is-biopterin.htm