In the de novo synthesis of purine nucleotides, IMP is the branch point metabolite at which point the pathway diverges to the synthesis of either guanine or adenine nucleotides. In the guanine nucleotide pathway, there are 2 enzymes involved in converting IMP to GMP, namely IMP dehydrogenase (IMPD1), which catalyzes the oxidation of IMP to XMP, and GMP synthetase, which catalyzes the amination of XMP to GMP.
This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds carbon-nitrogen ligases with glutamine as amido-N-donor. The systematic name of this enzyme class is xanthosine-5'-phosphate:L-glutamine amido-ligase (AMP-forming). Other names in common use include GMP synthetase (glutamine-hydrolysing), guanylate synthetase (glutamine-hydrolyzing), guanosine monophosphate synthetase (glutamine-hydrolyzing), xanthosine 5'-phosphate amidotransferase, and guanosine 5'-monophosphate synthetase. This enzyme participates in purine metabolism and glutamate metabolism. At least one compound, Psicofuranin is known to inhibit this enzyme.
^Tesmer JJ, Klem TJ, Deras ML, Davisson VJ, Smith JL (January 1996). "The crystal structure of GMP synthetase reveals a novel catalytic triad and is a structural paradigm for two enzyme families". Nat. Struct. Biol.3 (1): 74–86. doi:10.1038/nsb0196-74. PMID8548458.
Nakamura J, Straub K, Wu J, Lou L (1995). "The glutamine hydrolysis function of human GMP synthetase. Identification of an essential active site cysteine.". J. Biol. Chem.270 (40): 23450–5. doi:10.1074/jbc.270.40.23450. PMID7559506.
Fedorova L, Kost-Alimova M, Gizatullin RZ et al. (1997). "Assignment and ordering of twenty-three unique NotI-linking clones containing expressed genes including the guanosine 5'-monophosphate synthetase gene to human chromosome 3.". Eur. J. Hum. Genet.5 (2): 110–6. PMID9195163.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library.". Gene200 (1-2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Pegram LD, Megonigal MD, Lange BJ et al. (2001). "t(3;11) translocation in treatment-related acute myeloid leukemia fuses MLL with the GMPS (GUANOSINE 5' MONOPHOSPHATE SYNTHETASE) gene.". Blood96 (13): 4360–2. PMID11110714.
Guo D, Han J, Adam BL et al. (2005). "Proteomic analysis of SUMO4 substrates in HEK293 cells under serum starvation-induced stress.". Biochem. Biophys. Res. Commun.337 (4): 1308–18. doi:10.1016/j.bbrc.2005.09.191. PMID16236267.
Abrams R and Bentley M (1959). "Biosynthesis of nucleic acid purines. III. Guanosine 5'-phosphate formation from xanthosine 5'-phosphate and L-glutamine". Arch. Biochem. Biophys.79: 91–110. doi:10.1016/0003-9861(59)90383-2.
LAGERKVIST U (1958). "Biosynthesis of guanosine 5'-phosphate. II. Amination of xanthosine 5'-phosphate by purified enzyme from pigeon liver". J. Biol. Chem.233 (1): 143–9. PMID13563458.