Phosphoribosylglycinamide formyltransferase

Phosphoribosylglycinamide formyltransferase (<a href="/facts/Enzyme_Commission_number/Y5GNLRKX">EC</a> <a href="https://enzyme.expasy.org/EC/2.1.2.2">2.1.2.2</a>), also known as glycinamide ribonucleotide transformylase (GAR Tfase), is an <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a> with <a href="/facts/List_of_enzymes/w2RP6EwU">systematic name</a> 10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase. This enzyme <a href="/facts/Catalysis/LPBS7TQC">catalyses</a> the following <a href="/facts/Chemical_reaction/GpqWlKrz">chemical reaction</a>

<a href="/facts/10-Formyltetrahydrofolate/vfFuWbzs">10-formyltetrahydrofolate</a> + <a href="/facts/Glycineamide_ribonucleotide/cNSBsCVY">N1-(5-phospho-D-ribosyl)glycinamide</a> 
 
 
 
 ⇌
 
 
 {\displaystyle \rightleftharpoons }
 
 <a href="/facts/Tetrahydrofolate/6yEeP8JS">tetrahydrofolate</a> + <a href="/facts/Phosphoribosyl-N-formylglycineamide/QdCYLHUG">N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide</a>

This tetrahydrofolate (THF)–dependent enzyme catalyzes a nucleophilic acyl substitution of the formyl group from 10-formyltetrahydrofolate (fTHF) to N1-(5-phospho-D-ribosyl)glycinamide (GAR) to form N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide (fGAR) as shown above. This reaction plays an important role in the formation of purine through the de novo <a href="/facts/Purine_metabolism/mbRrRPDf">purine biosynthesis</a> pathway. This pathway creates <a href="/facts/Inosinic_acid/V3IevdQz">inosine monophosphate</a> (IMP), a precursor to <a href="/facts/Adenosine_monophosphate/D9Ryfqad">adenosine monophosphate</a> (AMP) and <a href="/facts/Guanosine_monophosphate/ex8VI4dR">guanosine monophosphate</a> (GMP). AMP is a building block for important energy carriers such as ATP, <a href="/facts/Nicotinamide_adenine_dinucleotide/BHdLW925">NAD+</a> and <a href="/facts/Flavin_adenine_dinucleotide/uzADx3ES">FAD</a>, and signaling molecules such as <a href="/facts/Cyclic_adenosine_monophosphate/flK2vwUe">cAMP</a>. GARTfase's role in de novo purine biosynthesis makes it a target for anti-cancer drugs and its overexpression during postnatal development has been connected to <a href="/facts/Down_syndrome/Y4XEQSMS">Down syndrome</a>. There are two known types of genes encoding GAR transformylase in <a href="/facts/Escherichia_coli/nR4Gvl56">Escherichia coli</a>: purN and purT, while only purN is found in humans. Many residues in the active site are conserved across bacterial, yeast, avian and human enzymes.

Phosphoribosylglycinamide formyltransferase open-in-new

Phosphoribosylglycinamide formyltransferase