Guanosine monophosphate reductase 1 (GMPR)

Guanosine monophosphate reductase 1 (GMPR1) is an NADPH-dependent enzyme critical for purine nucleotide metabolism and recycling[3][7]. It catalyzes the irreversible reductive deamination of guanosine monophosphate (GMP) to inosine monophosphate (IMP), providing the only known enzymatic route to recycle guanine nucleotides into adenine nucleotides via IMP, thus maintaining the proper intracellular balance of purine nucleotides[7][2]. The enzyme adopts a (α/β)_8 barrel fold and is typically found as a homotetramer[4][7]. GMPR activity is inversely regulated with inosine monophosphate dehydrogenase (IMPDH) and is modulated by cellular differentiation and nucleotide pool requirements[2]. In addition to its central metabolic function, altered GMPR expression is associated with some cancers, where downregulation can influence tumor progression by affecting guanine nucleotide pools and small G protein signaling[5]. No established drugs or therapeutic inhibitors against GMPR1 are currently in widespread clinical or preclinical use.

Other names

GMP reductase 1GMPR1Guanosine 5'-monophosphate oxidoreductase 1Guanine monophosphate reductaseGuanosine 5'-phosphate reductaseGuanosine monophosphate reductaseNADPH:GMP oxidoreductase (deaminating)NADPH:guanosine-5'-phosphate oxidoreductase (deaminating)Guanylate reductase

Inhibition or modulation affects purine nucleotide pools; decreases GTP and can affect small GTPase activity, e.g., RAC1 signaling in cancer cells[5]