Glycineamide ribonucleotide (or GAR) 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 GAR. :

GAR is the product of the enzyme

phosphoribosylamine—glycine ligase ''Phosphoribosylamine—glycine ligase'', also known as glycinamide ribonucleotide synthetase (GARS), () is an enzyme that catalyzes the chemical reaction :ATP + 5-phospho-D-ribosylamine + glycine \rightleftharpoons ADP + phosphate + which i ...

acting on phosphoribosylamine (PRA) to combine it with

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid ( carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinog ...

in a process driven by ATP. The reaction, forms an

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ...

bond: : + + ATP → + ADP + Pi The biosynthesis pathway next adds a formyl group from 10-formyltetrahydrofolate to GAR, catalysed by

phosphoribosylglycinamide formyltransferase Phosphoribosylglycinamide formyltransferase (, ''2-amino-N-ribosylacetamide 5'-phosphate transformylase'', ''GAR formyltransferase'', ''GAR transformylase'', ''glycinamide ribonucleotide transformylase'', ''GAR TFase'', ''5,10-methenyltetrahydrofol ...

in reaction and producing formylglycinamide ribotide (FGAR): :GAR + 10-formyltetrahydrofolate → FGAR + tetrahydrofolate

References

{{Nucleotide metabolism intermediates Nucleotides

See also

References