ImageFile = pterin structure.png
ImageSize = 200px
IUPACName = 2-amino-1H-pteridin-4-one
Section1 = Chembox Identifiers
CASNo = 2236-60-4
PubChem = 73000
SMILES = C1=CN=C2C(=N1)C(=O)N=C(N2)N
Section2 = Chembox Properties
MolarMass = 163.137
Section3 = Chembox Hazards
Pterin is a heterocyclic compound composed of a
pyrazinering and a pyrimidinering (a pteridinering system); the pyrimidine ring has a carbonyl oxygen and an amino group. Several tautomers of pterin exist and are shown below. As a group, "pterins" are compounds that are derivatives of 2-amino-4-oxopteridine, with additional functional groups attached to the pyrazine ring.
Pterins were first discovered in the pigments of
butterflywings (hence the origin of their name, from the Greek "pteron", wing) and perform many roles in coloration in the biological world. Pterins also function as cofactors in enzyme catalysis. Folates are “conjugated” pteridines which contain para-aminobenzoic acid and glutamates at the 6 position on the pteridine ring. They are critical compounds in a large number of biological group transfer reactions. These folate-dependent biosynthetic reactions include transfer of methyl groups to homocystine in the S-adenosyl methioninecycle, and transfer of formyl groups to methionineto form "N"-formylmethionine in initiator tRNAs.
Tautomers of pterin
The biosynthesis of pterins begins with the molecule
guanosine triphosphate(GTP); the enzyme which controls the conversion of GTP to pterin, GTP cyclohydrolase I, is found in both prokaryotes and eukaryotes.
Pterin can exist in many different forms in nature depending on its function.
Tetrahydrobiopterin, the major unconjugated pteridine in vertebrates, is a co-factor in the hydroxylation of aromatic compounds and synthesis of nitric oxide. Molybdopterinis a substituted pteridine that binds molybdenumto give redox enzymes involved in biological hydroxylations, reduction of nitrate, and respiratory oxidation. Tetrahydromethanopterinis used in methanogenic organisms. Cyanopterinis a glycosylated version of pteridine of unknown function in cyanobacteria.
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