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 puri ...

nucleotides Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both o ...

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 Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

and

RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...

. The vitamins

thiamine Thiamine, also known as thiamin and vitamin B1, is a vitamin – an Nutrient#Micronutrients, essential micronutrient for humans and animals. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosp ...

and

cobalamin Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. One of eight B vitamins, it serves as a vital cofactor (biochemistry), cofactor in DNA synthesis and both fatty acid metabolism, fatty acid and amino a ...

also contain fragments derived from FGAR. FGAR is formed when the enzyme

phosphoribosylglycinamide formyltransferase Phosphoribosylglycinamide formyltransferase (), also known as glycinamide ribonucleotide transformylase (GAR Tfase), is an enzyme with systematic name ''10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase''. This enzyme cat ...

adds a formyl group from 10-formyltetrahydrofolate to

glycineamide ribonucleotide Glycinamide ribonucleotide (or GAR) is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived ...

(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 (), 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