Phosphoribosyl-''N''-formylglycineamide (or FormylGlycinAmideRibotide, FGAR) is a biochemical intermediate in the formation of

purine Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines ...

nucleotides Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules with ...

via

inosine Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9- glycosidic bond. It was discovered in 1965 in analysis of RNA transferase. Inosine is commonly found in tRNAs and is ...

-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins

thiamine Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thi ...

and

cobalamin Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. ...

also contain fragments derived from FGAR. FGAR is formed when the enzyme phosphoribosylglycinamide formyltransferase adds a formyl group from 10-formyltetrahydrofolate to glycineamide ribonucleotide (GAR) in reaction : :GAR + 10-formyltetrahydrofolate → FGAR + tetrahydrofolate The biosynthesis pathway next converts FGAR to an

amidine Amidines are organic compounds with the functional group RC(NR)NR2, where the R groups can be the same or different. They are the imine derivatives of amides (RC(O)NR2). The simplest amidine is formamidine, HC(=NH)NH2. Examples of amidines includ ...

by the action of

phosphoribosylformylglycinamidine synthase In enzymology, a phosphoribosylformylglycinamidine synthase () is an enzyme that catalyzes the chemical reaction :ATP + ''N''2-formyl-''N''1-(5-phospho-D-ribosyl)glycinamide + L-glutamine + H2O \rightleftharpoons ADP + phosphate + 2-(formamido)- ...

(), transferring an amino group from glutamine and giving 5'-phosphoribosylformylglycinamidine (FGAM) in a reaction that also requires ATP: :FGAR + ATP + glutamine + H₂O → FGAM + ADP + glutamate + Pi

References

{{Nucleotide metabolism intermediates Nucleotides

See also

References