GMP reductase

GMP reductase EC 1.7.1.7 (Guanosine 5'-monophosphate oxidoreductase ) is an enzyme that catalyses the irreversible and NADPH-dependent reductive deamination of GMP into IMP.

NADPH + guanosine 5-phosphate = NADP⁺ + inosine 5-phosphate + NH₃

It converts nucleobase, nucleoside and nucleotide derivatives of G to A nucleotides, and maintains intracellular balance of A and G nucleotides.

In melanocytic cells, GMP reductase gene expression may be regulated by MITF.